Microwave Transmission Theory for On-Chip Ultrastrong-Coupled Magnon-Polariton in Dynamical Inductors
T. Chiba; T. Komine; and T. Aono, The Magnetics Society of Japan
J. Magn. Soc. Jpn., 2024年03月01日, ［査読有り］

Ultrastrong-coupled magnon-polariton in a dynamical inductor based on magnetic-insulator/topological-insulator bilayers
T. Chiba; T. Komine; and T. Aono, We theoretically study a magnon–polariton in a dynamical inductor consisting of a coil and a bilayer of ferromagnetic insulator (FI) with perpendicular magnetization and a three-dimensional topological insulator (TI). Taking into account the coherent magnetic-dipole (Zeeman) interaction as well as the dissipative spin pumping effect on the FI/TI interface, we formulate a dynamical permeability of the FI/TI bilayer and calculate a corresponding electric admittance of an RLC-circuit. As a result, the spin pumping gives rise to a competitive effect on the modes hybridization, whereas a huge level repulsion due to the coherent coupling, which reaches the ultrastrong coupling regime, is found at room temperature for realistic parameter sets. Our work may open a new avenue for designing on-chip microwave devices based on a magnon–polariton in the RLC-circuit., AIP Publishing
Appl. Phys. Lett., 2024年01月02日, ［査読有り］

Dynamical Nuclear Spin Polarization near Quantum Point Contact under Gaussian Disorder Potential
Tomosuke Aono
JPS Conference Proceedings, 2023年05月23日, ［査読有り］

Five and three quantum dot systems as apparatuses for measuring energy levels
Tetsufumi Tanamoto and Tomosuke Aono
Phys. Rev. B, 2022年09月01日, ［査読有り］

First Principle Band Calculations of Mg₂Si Thin Films with (001) and (110) Orientations　　　　　　　　　　　　　　　
Takizawa Masahisa; Komine Takashi; Udono Haruhiko; Aono Tomosuke
JJAP Conference Proceedings, 2020年08月03日, ［査読有り］

Quantum point contact potential curvature under correlated disorder potentials
T Aono; M Takahashi; M H Fauzi; Y Hirayama
Physical Review B, 2020年07月16日, ［査読有り］

Dipolelike dynamical nuclear spin polarization around a quantum point contact
Peter Stano; Tomosuke Aono; Minoru Kawamura, American Physical Society (APS)
Physical Review B, 2018年02月26日, ［査読有り］

Giant thermoelectric figure of merit in a noninteracting quantum dot system with massless Dirac fermions
Tomosuke Aono; Takashi Komine, We investigate the thermoelectric characteristics of a quantum dot system with massless Dirac fermions, in which the tunneling coupling between the quantum dot and the Dirac fermions has a pseudogap. The maximum values of the thermoelectric figure of merit and the thermopower can be made independent of temperature by tuning the energy level of the dot; the maximum value of the thermoelectric figure of merit is much greater than unity, and that of the thermopower is approximately 500 mu V/K. These characteristics also appear when the distance from the Dirac point to the Fermi level is lower than the thermal energy., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2016年10月, ［査読有り］

Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling
Takashi Komine; Tomosuke Aono, We demonstrate current-induced domain wall motion in bilayer nanowire with synthetic antiferromagnetic (SAF) coupling by modeling two body problems for motion equations of domain wall. The influence of interlayer exchange coupling and magnetostatic interactions on current-induced domain wall motion in SAF nanowires was also investigated. By assuming the rigid wall model for translational motion, the interlayer exchange coupling and the magnetostatic interaction between walls and domains in SAF nanowires enhances domain wall speed without any spin-orbit-torque. The enhancement of domain wall speed was discussed by energy distribution as a function of wall angle configuration in bilayer nanowires. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License., AMER INST PHYSICS
AIP ADVANCES, 2016年05月, ［査読有り］

Enhancement of Seebeck Coefficient in Bi Nanowires by Electric Field Effect
Takashi Komine; Tomosuke Aono; Yuta Nabatame; Masayuki Murata; Yasuhiro Hasegawa, In this study, we investigated the electric field effect on the transport properties of a Bi nanowire. These effects were modeled by a surface potential. The electron states of Bi nanowires were numerically analyzed by effective mass equations at the T-point and L-point taking into account surface potential due to an external electric field. The Seebeck coefficients of Bi nanowires were calculated by using the Boltzmann equation with a constant relaxation time. It was found that the Seebeck coefficients increased when the sign of the surface potential parameter was negative. In particular, when the surface potential parameter was -1 eV and the skin depth was 10 nm in a 20-nm-diameter nanowire, the maximum absolute value of the Seebeck coefficient was larger than 1 mV/K, which was greatly improved compared to that without an external electric field., SPRINGER
JOURNAL OF ELECTRONIC MATERIALS, 2016年03月, ［査読有り］

Tight-binding theory of surface spin states on bismuth thin films
Kazuo Saito; Hirokatsu Sawahata; Takashi Komine; Tomosuke Aono, The surface spin states for bismuth thin films are investigated using an sp(3) tight-binding model. The model explains most experimental observations using angle-resolved photoemission spectroscopy, including the Fermi surface, the band structure with Rashba spin splitting, and the quantum confinement in the energy band gap of the surface states. A large out-of-plane spin component also appears. The surface states penetrate inside the film to within approximately a few bilayers near the Brillouin-zone center, whereas they reach the center of the film near the Brillouin-zone boundary., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2016年01月, ［査読有り］

Transport properties for a quantum dot coupled to normal leads with a pseudogap
Bunpei Hara; Akihisa Koga; Tomosuke Aono, We study transport properties for a quantum dot coupled to normal leads with a pseudogap density of states at zero temperature, using the second-order perturbation theory based on the Keldysh formalism. We clarify that the hybridization function Gamma(omega) proportional to \omega\(r) (0 <= r < 1) induces the cusp or dip structure in the density of states in the dot when finite bias voltage is applied to the interacting quantum dot system. It is found that the current-voltage characteristics and differential conductance are drastically changed at r = 1/2., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2015年08月

Electronic Magnetization of a Quantum Point Contact Measured by Nuclear Magnetic Resonance
Minoru Kawamura; Keiji Ono; Peter Stano; Kimitoshi Kono; Tomosuke Aono, We report an electronic magnetization measurement of a quantum point contact (QPC) based on nuclear magnetic resonance (NMR) spectroscopy. We find that NMR signals can be detected by measuring the QPC conductance under in-plane magnetic fields. This makes it possible to measure, from Knight shifts of the NMR spectra, the electronic magnetization of a QPC containing only a few electron spins. The magnetization changes smoothly with the QPC potential barrier height and peaks at the conductance plateau of 0.5 x 2e(2)/h. The observed features are well captured by a model calculation assuming a smooth potential barrier, supporting a no bound state origin of the 0.7 structure., AMER PHYSICAL SOC
PHYSICAL REVIEW LETTERS, 2015年07月, ［査読有り］

Influence of classical electromagnetic effects on current-induced domain wall motion in a perpendicularly magnetized nanowire
Takashi Komine; Tomosuke Aono; Ryo Ando, The influence of classical electromagnetic effects such as applied current field and eddy current field on current-induced domain wall motion in a perpendicularly magnetized nanowire was investigated using a micromagnetic framework. The method used to calculate these fields was derived from Maxwell equation in order to estimate the effect of an attached non-magnetic (NM) layer. We demonstrate an applied current field and an eddy current field in a perpendicularly magnetized nanowire with and without a non-magnetic layer. Without a NM layer, the eddy current field causes a small correction in the Gilbert damping with a wall angle dependence. Adding a NM layer enhances the effective Gilbert damping, especially, in terms of wall rotation. Furthermore, an applied current field strongly affects the current-induced domain wall motion, and significantly changes the critical current density and the Walker breakdown. (C) 2015 AIP Publishing LLC., AMER INST PHYSICS
JOURNAL OF APPLIED PHYSICS, 2015年05月, ［査読有り］

Conductance and Thermopower of Dirac Fermions under the Kondo Effect
Tomosuke Aono
JPS Conf. Proc., 2014年06月16日, ［査読有り］

Solid evidence for magnetic moment enhancement in micro-particles of Mn11Si19
Kiyotaka Hammura; Haruhiko Udono; Tomosuke Aono, We study magnetic properties of Mn11Si19 both in a bulk and in a powder (the averaged diameter of particles was about 5 μm) states. The bulk sample was grown using the temperature gradient solution method, and the powder sample was obtained through pounding the bulk sample in a mortar. We measured magnetisation as a function of temperature using a SQUID magnetometer. We found that the bulk sample was paramagnetic while the power sample was soft ferromagnetic. The magni- tude of the magnetisation of the powder sample was al- most unchanged between5K to 300 K. © 2013 WILEY-VCH Verlag GmbH &
Co. KGaA, Weinheim.
Physica Status Solidi (C) Current Topics in Solid State Physics, 2013年12月, ［査読有り］

Electrical and thermoelectrical transport properties of dirac fermions through a quantum dot
Tomosuke Aono, We investigate the conductance and thermopower of massless Dirac fermions through a quantum dot using a pseudogap Anderson model in a noncrossing approximation. When the Fermi level is at the Dirac point, the conductance has a cusp where the thermopower changes its sign. When the Fermi level is away from the Dirac point, the Kondo temperature shows a quantum impurity transition between an asymmetric strong-coupling Kondo state and a localized moment state. The conductance shows a peak near this transition and reaches the unitary limit at low temperatures. The magnitude of the thermopower exceeds kB=e, and the thermoelectric figure of merit exceeds unity. © 2013 The Physical Society of Japan.
Journal of the Physical Society of Japan, 2013年08月, ［査読有り］

Magnetisation of bulk Mn11Si19 and Mn4Si7
K. Hammura; H. Udono; I. J. Ohsugi; T. Aono; E. De Ranieri, The purpose of this paper is to determine by experiment whether Mn11Si19 and Mn4Si7 in their bulk states have a finite magnetic moment or not. Magnetisation measurements were carried out on these materials using both SQUID system and Kerr rotation system. The high quality samples were grown using the temperature gradient solution growth method. SQUID measurements revealed that Mn11Si19 has finite magnetism while Mn4Si7 does not in their bulk states. It was also confirmed that Mn4Si7 became magnetic and Mn11Si19 got to exhibit a distinctive hysteresis in their powdery state. The enhancement of magnetism implied that the surface of the samples was to a great extent linked to its magnetism. (C) 2011 Elsevier B. V. All rights reserved., ELSEVIER SCIENCE SA
THIN SOLID FILMS, 2011年10月, ［査読有り］

Numerical Study of Effect of Surface Potential on Transport Properties of Bi Nanowires
Tsuyoshi Matsumoto; Yuki Ichige; Takashi Komine; Ryuji Sugita; Tomosuke Aono; Masayuki Murata; Daiki Nakamura; Yasuhiro Hasegawa, We numerically investigated the effect of the surface on the transport properties of Bi nanowires. The effect of the surface was modeled using the surface potential. The energy shift in each band due to the surface potential was calculated by a perturbation method. The effect of the surface potential on the transport properties was estimated using the Boltzmann equation with a constant relaxation time. The results reveal that the surface potential dramatically alters the density of states of T-point holes, whereas it has very little effect on the density of states of L-point holes. This is because the wavefunctions at the L- and T-points have different symmetries. The electrical conductivity increases and the Seebeck coefficient decreases with increasing surface potential. The maximum absolute value of the Seebeck coefficient decreases drastically with increasing surface potential. The Seebeck coefficient has a much stronger dependence on the surface potential than on the wire diameter. These results demonstrate that the transport properties of Bi nanowires are very sensitive to the surface potential., SPRINGER
JOURNAL OF ELECTRONIC MATERIALS, 2011年05月, ［査読有り］

Numerical Analysis of Effect of Scattering Process on Transport Properties in Bi Nanowires
Y. Ichige; T. Matsumoto; T. Komine; R. Sugita; T. Aono Y. Hasegawa; M. Murata; and D. Nakamura, In this study, we investigated the effects of scattering on the transport properties of Bi nanowires. The electrical conductivities and Seebeck coefficients of Bi nanowires were calculated using the Boltzmann equation, with an energy-dependent relaxation time corresponding to the scattering process. Decreasing the wire diameter increased the Seebeck coefficient for all of the scattering processes examined, because a semimetal-semiconductor transition occurred. In 80-nm-diameter nanowires, the Seebeck coefficient for ionized impurity scattering was larger than that of the acoustic deformation potential. On the other hand, in 20-nm-diameter nanowires, the dependence of the Seebeck coefficient on the scattering process was negligible, compared with the influence of wire diameter., SPRINGER
J. Elec. Mater., 2010年11月25日, ［査読有り］

Dephasing in a quantum dot coupled to a quantum point contact
Tomosuke Aono, We investigate a dephasing mechanism in a quantum dot capacitively coupled to a quantum point contact. We use a model which was proposed to explain the 0.7 structure in point contacts, based on the presence of a quasibound state in a point contact. The dephasing rate is examined in terms of charge fluctuations of electrons in the bound state. We address a recent experiment by Avinun-Kalish [Phys. Rev. Lett. 92, 156801 (2004)], where a double-peak structure appears in the suppressed conductance through the quantum dot. We show that the two conducting channels induced by the bound state are responsible for the peak structure., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2008年02月, ［査読有り］

Two impurity Kondo problem under Aharonov-Bohm and Aharonov-Casher effects
Tomosuke Aono, We investigate electron transport under the two impurity Kondo problem with the Aharonov-Bohm and Aharonov-Casher effects. These interference effects induce the Ising-coupled Ruderman-Kittel-Kasuya-Yosida interaction. We discuss the inter- and intrasite spin conductance as well as charge conductance in the Kondo and the mixed-valence regimes using the slave boson mean field approximation., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2007年08月, ［査読有り］

Interference effects in an Aharonov–Bohm ring with random quantum dot
Tomosuke Aono; Kazutaka Takahashi, We investigate electron transport through quantum dots embedded in an Aharonov-Bohm ring. One or both of the dots are chaotic and are treated by random matrix theory. The conductance and conductance fluctuations are calculated as a function of the ratio of the level broadening to the average level spacing in the random dots using random scattering matrix theory with a Poisson kernel. Several interference mechanisms in the ring are examined. When one random dot and a single resonance level coexist and the multiple reflection between them is taken into account, the conductance is suppressed as the Fermi level of the leads approaches resonance in the large level broadening regime. For coupled random dot systems, characterized by two different ratios, the conductance is sensitive to the difference between the ratios when the multiple scattering inside the ring is disregarded, while it does not depend on the difference when the scattering is effective., IOP PUBLISHING LTD
New Journal of Physics, 2007年05月, ［査読有り］

Chaotic scattering through coupled cavities
Kazutaka Takahashi; Tomosuke Aono, We study the chaotic scattering through an Aharonov-Bohm ring containing two cavities. One of the cavities has well-separated resonant levels while the other is chaotic, and is treated by random matrix theory. The conductance through the ring is calculated analytically using the supersymmetry method and the quantum fluctuation effects are numerically investigated in detail. We find that the conductance is determined by the competition between the mean and fluctuation parts. The dephasing effect acts on the fluctuation part only. The Breit-Wigner resonant peak is changed to an antiresonance by increasing the ratio of the level broadening to the mean level spacing of the random cavity, and the asymmetric Fano form turns into a symmetric one. For the orthogonal and symplectic ensembles, the period of the Aharonov-Bohm oscillations is half of that for regular systems. The conductance distribution function becomes independent of the ensembles at the resonant point, which can be understood by the mode-locking mechanism. We also discuss the relation of our results to the random walk problem., AMER PHYSICAL SOC
PHYSICAL REVIEW E, 2007年02月, ［査読有り］

Suppression of Shot Noise in Quantum Point Contacts in the “0.7 Regime”
A Golub; T Aono; Yigal Meir, Experimental investigations of current shot noise in quantum point contacts show a reduction of the noise near the 0.7 anomaly. It is demonstrated that such a reduction naturally arises in a model proposed recently to explain the characteristics of the 0.7 anomaly in quantum point contacts in terms of a quasibound state, due to the emergence of two conducting channels. We calculate the shot noise as a function of temperature, applied voltage, and magnetic field, and demonstrate an excellent agreement with experiments. It is predicted that, with decreasing temperature, voltage, and magnetic field, the dip in the shot noise is suppressed due to the Kondo effect., AMERICAN PHYSICAL SOC
Phys. Rev. Lett., 2006年11月, ［査読有り］

Mesoscopic conductance fluctuations in a coupled quantum dot system
Kazutaka Takahashi; Tomosuke Aono, We study the transport properties of an Aharonov-Bohm ring containing two quantum dots. One of the dots has well-separated resonant levels, while the other is chaotic and is treated by random matrix theory. We find that the conductance through the ring is significantly affected by mesoscopic fluctuations. The Breit-Wigner resonant peak is changed to an antiresonance by increasing the ratio of the level broadening to the mean level spacing of the random dot. The asymmetric Fano form turns into a symmetric one and the resonant peak can be controlled by magnetic flux. The conductance distribution function clearly shows the influence of strong fluctuations., AMERICAN PHYSICAL SOC
PHYSICAL REVIEW B, 2006年07月, ［査読有り］

Adiabatic pumping through a quantum dot under the Kondo effect
T Aono, Adiabatic pumping through a quantum dot is investigated under the strong Coulomb interaction using the slave boson mean-field theory. The pumped current is driven by time-dependent gate voltages applied to the dot. We illustrate the pumped current peculiar to the Kondo effect. (c) 2005 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
PHYSICA B-CONDENSED MATTER, 2005年04月, ［査読有り］

Adiabatic pumping in the mixed-valence and Kondo regimes
T Aono, We investigate adiabatic pumping through a quantum dot with a single level in the mixed-valence and Kondo regimes using the slave boson mean field approximation. The pumped current is driven by a gauge potential due to time-dependent tunneling barriers as well as by the modulation of the Friedel phase. The sign of the former contribution depends on the strength of the Coulomb interaction. Under finite magnetic fields, the separation of the spin and charge currents peculiar to the Kondo effect occurs., AMER PHYSICAL SOC
PHYSICAL REVIEW LETTERS, 2004年09月, ［査読有り］

Kondo effect in p-wave superconducting junctions
T Aono; A Golub; Y Avishai, We investigate electron transport through quantum dot in the Kondo regime with p-wave superconducting leads when T-K > Delta. The current and the shot-noise power are calculated as functions of the applied voltage in the sub-gap region eV < Delta. In addition, the Josephson current is calculated as function of temperature and phase. We point out the qualitative difference between junctions with s-wave and p-wave superconducting leads. (C) 2003 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 2004年04月, ［査読有り］

Quantum dot in the Kondo regime coupled to p-wave superconductors
T Aono; A Golub; Y Avishai, The physics of junctions containing p-wave superconducting and normal leads weakly coupled to an Anderson impurity in the Kondo regime is elucidated. For p-wave (unlike s wave) superconducting leads, midgap surface states play an important role in the tunneling process and help the formation of the Kondo resonance. The current, shot-noise power, and Fano factor are calculated and displayed as functions of the applied voltage V in the subgap region eV < Delta (the superconducting gap). In addition, the Josephson current for a quantum dot in the Kondo regime weakly coupled on both sides to p-wave superconductors is computed as function of temperature and phase. The peculiar differences between the cases of s-wave and p-wave superconducting leads are pointed out., AMER PHYSICAL SOC
PHYSICAL REVIEW B, 2003年07月, ［査読有り］

Adiabatic electron pumping through a quantum dot with a discrete level
T Aono, An adiabatic electron pumping through a quantum dot with a discrete energy level under a magnetic field is investigated theoretically. Adiabatic spin pumping takes place under two time-dependent external sources, the Zeeman energy and the difference in the tunneling coupling to the dot between the left and right leads. The behavior of the pumped spin as a function of the amplitude of the magnetic field is different whether the dot level is above the Fermi level in leads. (C) 2003 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE BV
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 2003年05月, ［査読有り］

Adiabatic spin pumping through a quantum dot with a single orbital level
Tomosuke Aono, We investigate an adiabatic spin pumping through a quantum dot with a single orbital energy level under the Zeeman effect. Electron pumping is produced by two periodic time dependent parameters, a magnetic field, and a difference of the dot-lead coupling between the left and right barriers of the dot. The maximum charge transfer per cycle is found to be e, the unit charge in the absence of a localized moment in the dot. Pumping rates for charge and spin are different, so that spin pumping is possible without charge pumping in a certain situation. They are tunable by changing the minimum and maximum value of the magnetic field., AMER PHYSICAL SOC
Phys Rev B, 2003年04月03日, ［査読有り］

Kondo effect in coupled quantum dots under magnetic fields
Tomosuke Aono; Mikio Eto, The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates the peak structures of Kondo resonant spectra. When the dot-dot tunneling coupling Vc is smaller than the dot-lead coupling Δ (level broadening), Kondo resonant levels appear at the Fermi level (EF). The Zeeman splitting of the levels weakens the Kondo effect, which results in a negative MC. When Vc is larger thanΔ, the Kondo resonances form bonding and antibonding levels, located below and above EF, respectively. We observe a positive MC since the Zeeman splitting increases the overlap between the levels at EF. In the presence of antiferromagnetic spin coupling between the dots, the sign of the MC can change as a function of the gate voltage.
Physical Review B - Condensed Matter and Materials Physics, 2001年08月15日, ［査読有り］

Kondo resonant spectra in coupled quantum dots
Tomosuke Aono and Mikio Eto, The Kondo effect in coupled quantum dots is investigated from the viewpoint of transmission spectroscopy using the slave-boson formalism of the Anderson model. The antiferromagnetic spin-spin coupling J between the dots is taken into account. Conductance G through the dots connected in a series is characterized by the competition between the dot-dot tunneling coupling Ve and the level broadening Delta in the dots (dot-lead coupling). When V-C/Delta < 1, the Kondo resonance is formed between each dot and lead, which is replaced by a spin-singlet state in the dots at low gate voltages. The gate voltage dependence of G has a sharp peak of 2e(2)/h in height in the crossover region between the Kondo and spin-singlet states. The sharp peak of G survives when the energy levels are different between the dots. When V-C/<Delta> >1, the "molecular levels" between the Kondo resonant states appear: the Kondo resonant peaks are located below and above the Fermi level in the leads at low gate voltages. The gate voltage dependence of G has a broad peak, which is robust against J. The broad peak splits into two peaks when the energy levels are different, reflecting the formation of the asymmetric molecular levels between the Kondo resonant states., AMER PHYSICAL SOC
Phys Rev B, 2001年03月13日, ［査読有り］

Kondo effect on the transport properties of asymmetric dimer of quantum dots
T Aono; M Eto, The Kondo effect in asymmetric quantum dot dimer connected in series is studied based on the slave boson formalism of the Anderson model. When the dot-dot tunneling coupling is larger than the level broadening, the bonding and antibonding peaks of the Kondo resonances are observed. When the energy level difference between the two dots is large, the plateau structure of the conductance as a function of the gate voltage appears. The conductance at the plateau decreases as the dot-dot coupling increases, reflecting larger splitting of the bonding and anti-bonding peaks. (C) 2000 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE BV
PHYSICA B, 2000年07月, ［査読有り］

Electron transport through coupled quantum dots below the Kondo temperature
T Aono; M Eto, Conductance G through coupled quantum dots in series is investigated below the Kondo temperature, based on the slave boson formalism of the Anderson model with the antiferromagnetic spin-spin coupling J. Electron transport is characterized by the ratio of the dot-dot tunneling coupling V-C to the level broadening in the dots Delta (dot-lead coupling). When V-C/Delta < 1, the Kondo resonance is formed in each dot and lead and G is determined by hopping between the two Kondo states. They are replaced by a spin-singlet state in the dots for low gate voltages. The gate voltage dependence of G has a sharp peak of 2e(2)/h in height in the crossover region between the spin-singlet and Kondo states. When V-c/Delta > 1, the Kondo levels are split below and above the Fermi level in the leads for low gate voltages. The gate voltage dependence of G has a broad peak, which is fairly robust against J. This broad peak is divided into two peaks when the energy levels are different between the dots., KLUWER ACADEMIC/PLENUM PUBL
JOURNAL OF LOW TEMPERATURE PHYSICS, 2000年03月, ［査読有り］

Phenomenological theory of the Rabi oscillation in coupled quantum dots
T Aono; K Ishibashi; Y Aoyagi, We study theoretically electron transport through coupled quantum dots under the sequence of pulse voltages in order to see how the Rabi oscillation is demonstrated like atoms' fluorescence in two-level atoms. The Rabi oscillation of the current as a function of the pulse duration is obtained. The effect of inelastic scattering is also discussed. (C) 1999 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE BV
PHYSICA B, 1999年12月, ［査読有り］

Linear Conductance through Parallel Quantum Dot Dimer below the Kondo Temperature
Tomosuke Aono; Mikio Eto; Kiyoshi Kawamura, The conductance through two quantum dots connected in a series is examined below the Kondo temperature as a function of the gate voltage attached to the dots. The ratio of the tunneling coupling between two dots to the level broadening characterizes the transport properties. When the ratio is less than unity, each dot accommodates one electron and forms the Kondo resonant state with an external lead at a sufficiently low gate voltage. In the valence fluctuating regime, the number of electrons in the dots decreases from two to zero whereas the conductance is suppressed. The corresponding range of the gale voltage is nearly the level broadening. When the ratio is larger than unity, the Kondo resonances arc split into the bonding and antibonding peaks. The valence fluctuating regime is extended over the tunneling coupling between the two dots., Japan Society of Applied Physics
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, 1999年, ［査読有り］

Conductance through quantum dot dimer below the Kondo temperature
Tomosuke Aono; Mikio Eto; Kiyoshi Kawamura, The conductance through two quantum dots connected in series is studied below the Kondo temperature, based on the slave boson formalism of the Anderson model. The transport properties are characterized by the ratio of the magnitude of the tunneling coupling between two dots to the width of the level broadening. When the ratio is less than unity, the Kondo resonant states are formed between each dot and an external lead, and the conductance is determined by the hopping between the two resonant states. When the ratio is larger than unity, these Kondo resonances are split into the bonding and antibonding peaks, which are located below and above the Fermi level in the leads, respectively, for low gate voltages. As a result, the conductance is suppressed. The conductance has a maximum of 2e2/h when the bonding peak is matched with the Fermi level by controlling the gate voltage., Physical Society of Japan
Journal of the Physical Society of Japan, 1998年, ［査読有り］

Theory of single electron tunneling through a quantum dot dimer
K Kawamura; T Aono, Transport spectra of a quantum dot dimer are studied with the assumption that energy levels are quantized in each quantum dot. The splitting of energy levels between bonding and antibonding states is modulated by the coupling with electronic states in an emitter and a collector. When the coupling with external electrodes is strong enough, the spectra of a quantum dot dimer are not necessarily observed by I-V characteristics., JAPAN J APPLIED PHYSICS
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 1997年06月, ［査読有り］

Double quantum dots as dissipative two level systems
T Aono; K Kawamura, A double quantum dot system is a typical example of a dissipative two level system. The ratio of the coupling of the two dots and the width of the energy level is the important parameter determining whether the quantum coherence can be seen clearly. Indications of quantum coherence between two dots appear not only in the stationary states but also in the relaxation processes from non-stationary states., JAPAN J APPLIED PHYSICS
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 1997年06月, ［査読有り］

Relaxation of Non-Stationary States due to a Sudden Change of an Energy Level in a Quantum Dot.
Tomosuke Aono, A relaxation process is studied quantum mechanically in a quantum dot which is weakly coupled to two electrodes, using the real time path integration method. We consider the following situation: at first, the stationary current flows through the quantum dot which has a single energy level <(omega)over bar>(0). After a sudden change in the dot level to omega(0), the electronic state starts to relax to another stationary state. We investigate the transient behaviors of the number of electrons in the dot and the current through the barriers. They oscillate with the frequencies (omega(0)-mu(nu)), where mu(nu) (mu=L, R) are the Fermi levels of two electrodes. The relative phase of these oscillation is determined by omega(0)-<(omega)over bar>(0). The quantum effects decreases with time slower than the ordinary exponential decaying given by the master equation., PHYSICAL SOC JAPAN
J. Phys. Soc. Jpn, 1997年03月15日, ［査読有り］

平らなポテンシャル構造をもつ量子ポイントコンタクト近傍でのスピン分極　　　　　　　　　　　　　　　
青野友祐
日本物理学会2025年春季大会, 2025年03月21日

Microwave Transmission Theory for Ultrastrong-Coupled Magnon-Polariton in Dynamical Inductors　　　　　　　　　　　　　　　
千葉貴裕; 小峰啓史; 青野友祐
テラヘルツ科学の最先端X, 2023年12月20日

Microwave Transmission Theory for On-Chip Ultrastrong-Coupled Magnon-Polariton in Dynamical Inductors　　　　　　　　　　　　　　　
Takahiro Chiba; Takashi Komine; Tomosuke Aono
The 7th Symposium for the Core Research Clusters for Materials Science and Spintronics and the 6th Symposium on International Joint Graduate Program in Materials Science and Spintronics, 2023年11月28日

トポロジカル絶縁体/磁性絶縁体二層膜における強結合磁気共鳴　　　　　　　　　　　　　　　
千葉貴裕; 小峰啓史; 青野友祐
第47回 日本磁気学会学術講演会, 2023年09月27日

グリーン関数法を用いた量子準位測定系としての多量子ドット系の理論的考察　　　　　　　　　　　　　　　
棚本哲史; 青野友祐
日本物理学会 2023年春季大会, 2023年03月24日

乱れポテンシャルのある量子ポイントコンタクトにおける動的核スピン分極　　　　　　　　　　　　　　　
青野友祐
日本物理学会 2023年春季大会, 2023年03月23日

Nuclear spin polarization near quantum point contact under Gaussian disorder potential　　　　　　　　　　　　　　　
Tomosuke Aono
29th International Conference on Low Temperature Physics (LT29), 2022年08月23日

畳み込みニューラルネットワークを用いた入力画像のズレに対する画像分類　　　　　　　　　　　　　　　
令和３年度（第29回）茨城支所研究発表会, 2021年12月11日

量子細線における不純物効果の深層学習による推定　　　　　　　　　　　　　　　
児玉 陽一、長谷川 伸、野木沼 真海、竹田 晃人、青野 友祐
第82回応用物理学会秋季学術講演会, 2021年09月11日

Gaussian disorder potential effect on electron transport through quantum point contacts　　　　　　　　　　　　　　　
T. Aono; M. Takahashi; M. H. Fauzi; Y. Hirayama
International Symposium on Hybrid Quantum Systems 2019 (HQS2019), 2019年12月04日

Correlated Disorder Potential Effect on the Conductance through Quantum Point Contacts　　　　　　　　　　　　　　　
T. Aono; M. Takahashi; M. H. Fauzi; Y. Hirayama
International School and Symposium on Nanoscale Transport and phoTonics 2019, 2019年11月19日

First principle band calculations of Mg2Si thin films　　　　　　　　　　　　　　　
M. Takizawa; T. Komine; H. Udono; T. Aono
The Fifth Asia-Pacific Conference on Semiconducting Silicides and Related Materials, APAC-SILICIDE 2019, 2019年07月20日

Disorder potential effect on electron transport through quantum point contacts　　　　　　　　　　　　　　　
T. Aono; M. Takahashi; M. H. Fauzi; Y. Hirayama
The 21st International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON21), 2019年07月16日

Nuclear spin polarization and its detection in quantum point contacts　　　　　　　　　　　　　　　
T. Aono
The 2019 Frontiers in Quantum Materials and Devices workshop (FQMD2019), 2019年05月27日

Nuclear spin polarization in a quantum point contact　　　　　　　　　　　　　　　
Tomosuke Aono; Peter Stano; Minoru Kawamura
International Symposium on Frontiers of Quantum Transport in Nano Science, 2018年11月09日

面内磁場下の量子ポイントコンタクトにおける動的核スピン偏極　　　　　　　　　　　　　　　
青野友祐、Peter Stano、 川村稔、大野圭司、小峰啓史
日本物理学会 第73回年次大会（2018年）, 2018年03月24日

Nuclear spin polarization and resistively-detected nuclear magnetic resonance in quantum point contact　　　　　　　　　　　　　　　
Tomosuke Aono; Peter Stano; Minoru Kawamura; Keiji Oono; Takashi Komine
2017 Workshop on Innovative Nanoscale Devices and Systems (WINDS), 2017年11月30日

Electron transport in a quantum point contact with hyperfine interaction under finite magnetic field　　　　　　　　　　　　　　　
T. Aono; M. Kawamura; P. Stano; K. Ono; T. Komine
International symposium on hybrid quantum systems 2017 (HQS2017), 2017年09月11日

Electronic states in quantum point contacts with flat potential barriers　　　　　　　　　　　　　　　
Tomosuke Aono
International symposium on hybrid quantum systems 2017 (HQS2017), 2017年09月11日

磁場中の量子ポイントコンタクトにおける電子状態と電気伝導 II
青野 友祐; 川村 稔; 大野 圭司; Stano Peter; 小峰 啓史
2017年度日本物理学会第72回年次大会, 2017年03月17日, 一般社団法人 日本物理学会

BiSb合金薄膜の表面電子状態のタイトバインディング法による数値解析II
澤田 雄大; 永井 潤也; 小峰 啓史; 青野 友祐
2016年度日本物理学会秋季大会, 2016年09月13日, 一般社団法人 日本物理学会

BiSb合金薄膜の表面電子状態のタイトバインディング法による数値解析
永井 潤也; 澤田 雄大; 小峰 啓史; 青野 友祐
2016年度日本物理学会秋季大会, 2016年09月13日, 一般社団法人 日本物理学会

磁場中の量子ポイントコンタクトにおける電子状態と電気伝導
青野 友祐; 川村 稔; 大野 圭司; 小峰 啓史
2016年度日本物理学会秋季大会, 2016年09月13日, 一般社団法人 日本物理学会

Surface spin states of bismuth thin films: a tight-binding analysis　　　　　　　　　　　　　　　
K. Saito; H. Sawahata; J. Nagai; Y. Sawada; T. Komine; T. Aono
th International Conference on Physics and Applications of Spin-Related Phenomena in Solid, 2016年08月10日

Current-driven dynamical nuclear spin polarization in a semiconductor quantum point contac　　　　　　　　　　　　　　　
Minoru Kawamura; Keiji Ono; Peter Stano; Kimitoshi Kono; Tomosuke Aono
9th International Conference on Physics and Applications of Spin-Related Phenomena in Solids, 2016年08月09日

Tight-binding model analysis on surface spin states of bismuth-antimony alloy thin films　　　　　　　　　　　　　　　
J. Nagai; Y. Sawada; T. Komine; T. Aono
9th International Conference on Physics and Applications of Spin-Related Phenomena in Solids, 2016年08月08日

Electronic states of bismuth thin films: a tight-binding analysis　　　　　　　　　　　　　　　
K. Saito; H. Sawahata; J. Nagai; Y. Sawada; T. Komine; T. Aono
The 22nd International Conference on High Magnetic Fields in Semiconductor Physics, 2016年07月25日

Tight-Binding Theory of Surface Spin States on Bismuth Thin Films　　　　　　　　　　　　　　　
Kazuo Saito; Hirokatsu Sawahata; Takashi Komine; Tomosuke Aono
Frontiers in Quantum Materials and Devices Workshop FQMD2016, 2016年06月13日

ビスマスナノ構造における表面状態の数値解析　　　　　　　　　　　　　　　
青野友祐,小峰啓史,村田正行,長谷川靖洋
2016年第63回応用物理学会春季学術講演会, 2016年03月19日

ディラック電子中の量子ドットによる熱電特性の解析　　　　　　　　　　　　　　　
青野友祐,小峰啓史
日本物理学会第71回年次大会2016, 2016年03月19日

Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling　　　　　　　　　　　　　　　
T. Komine; T. Aono
2016 Joint MMM-Intermag Conference, 2016年01月12日

Tight-binding theory of surface spin states on bismuth thin films　　　　　　　　　　　　　　　
Tomosuke Aono
Physics of bulk-edge correspondences & its universality: From solid state physics to cold atoms, International Workshop, 2015, 2015年09月29日

量子ポイントコンタクトにおける動的核スピン偏極　　　　　　　　　　　　　　　
川村 稔 and 大野 圭司 and Peter Stano and 河野 公俊 and 青野 友祐
日本物理学会 2015 年秋季大会, 2015年09月18日

積層型ナノワイヤにおける層間交換結合が電流誘起磁壁移動に及ぼす影響　　　　　　　　　　　　　　　
小峰啓史、青野友祐
第76回 応用物理学会秋季学術講演会, 2015年09月13日

Numerical analysis of surface spin states on bismuth thin films　　　　　　　　　　　　　　　
K. Saito; H. Sawahata; T. Komine; T. Aono
1st International Conference on Electronic Properties of Two-Dimensional Systems (EP2DS) & 17th International Conference on Modulated Semiconductor Structures(MSS), 2015年07月28日

Enhancement of Seebeck coefficient in Bi nanowires by electric field effect　　　　　　　　　　　　　　　
T. Komine; T. Aono; Y. Nabatame; M. Murata; Y. Hasegawa
The 34th International & 13th European Conference on Thermoelectrics (ICT&ECT), 2015年06月30日

ビスマス薄膜表面におけるスピン分極の数値解析　　　　　　　　　　　　　　　
齊藤和雄; 青野友祐; 小峰啓史
日本物理学会第 70 回年次大会(2015 年), 2015年03月23日

積層構造ナノワイヤにおける電流誘起磁壁移動の数値解析　　　　　　　　　　　　　　　
小峰啓史,青野友祐,安藤亮
2016年第63回応用物理学会春季学術講演会, 2015年03月19日

18pAE-5 量子ポイントコンタクトにおける動的核スピン偏極
川村 稔; 大野 圭司; Peter Stano; 河野 公俊; 青野 友祐
日本物理学会講演概要集, 2015年, 一般社団法人 日本物理学会

Electric and thermoelectric transport properties of Dirac Fermions through a quantum dot　　　　　　　　　　　　　　　
Tomosuke Aono
International Conference on Strongly Correlated Electron Systems (SCES 2013), 2013年08月

Solid evidence for magnetic moment enhancement in micro-particles of Mn11Si19　　　　　　　　　　　　　　　
Kiyotaka Hammura; Haruhiko Udono; Tomosuke Aono
Asia-Pacific Conference on Green Technology with Silicides and Related Materials : APAC-SILICIDE 2013, 2013年07月29日

Electric and thermoelectric transport properties of Dirac fermions under the Kondo effect　　　　　　　　　　　　　　　
Tomosuke Aono
QS2C Theory Forum: International Symposium on“Strongly Correlated Quantum Science, 2013年01月27日

ビスマス微細構造における電子状態　　　　　　　　　　　　　　　
電気学会東京支部茨城支所発表会, 2010年11月14日

Mn₁₁Si₁₉とMn₄Si₇結晶の磁気特性　　　　　　　　　　　　　　　
第71回応用物理学会学術講演会, 2010年09月16日

Magnetization of bulk Mn11Si19 and Mn4Si7 crystals　　　　　　　　　　　　　　　
APAC-SILICIDE 2010, 2010年07月24日

日本物理学会