94 citations · 320 across the 29 of their papers we have counts for
29 papers
Dispersive detection of a charge qubit with a broadband high-impedance quantum-Hall plasmon resonator
Chaojing Lin, Kosei Teshima, Takafumi Akiho +2
Cavity quantum electrodynamics (cQED) provides strong light-matter interactions that can be used for manipulating and detecting quantum states. The interaction can be enhanced by i…
Efficient heat-energy conversion from a non-thermal Tomonaga-Luttinger liquid
Hikaru Yamazaki, Masashi Uemura, Haruhi Tanaka +5
Energy harvesting is a technique that generates useful work from waste heat. Conventional energy harvesters acting on local thermal equilibrium states are constrained by thermodyna…
Effects of GaAs Buffer Layer on Structural, Magnetic, and Transport Properties of Magnetic Topological Insulators Cr(BiSb)Te and V(BiSb)Te Films
Yusuke Nakazawa, Takafumi Akiho, Kiyoshi Kanisawa +3
Here, we study the effects of a GaAs buffer layer on the structural, magnetic, and transport properties of Cr(BiSb)Te magnetic topological insulator thi…
Coulomb oscillations of a quantum antidot formed by an airbridged pillar gate in the integer and fractional quantum Hall regime
Tokuro Hata, Hiroki Mitani, Hidetaka Uchiyama +3
Quantum antidots (QAD) are attractive for manipulating quasiparticles in quantum Hall (QH) systems. Here, we form a QAD in the integer and fractional QH regimes at nominal Landau-l…
Static quantum dot on a potential hilltop for generating and analyzing hot electrons in the quantum Hall regime
Ryo Oishi, Yuto Hongu, Tokuro Hata +4
We propose and demonstrate a static quantum dot on a potential hilltop to generate and analyze ballistic hot electrons along a quantum Hall edge channel well above the chemical pot…
Andreev Reflection in the Quantum Hall Regime at an Al/InAs Junction on a Cleaved Edge
Takafumi Akiho, Hiroshi Irie, Yusuke Nakazawa +3
We have fabricated a superconductor/semiconductor (S/Sm) junction composed of Al and InAs using cleaved edge overgrowth. By exploiting the unique geometry with a thin Al/Pt/Al tril…
Effects of GaAs buffer layer on quantum anomalous Hall insulator Vy(BixSb1-x)2-yTe3
Yusuke Nakazawa, Takafumi Akiho, Kiyoshi Kanisawa +3
We report the growth, structural characterization, and transport properties of the quantum anomalous Hall insulator Vy(BixSb1-x)2-yTe3 (VBST) grown on a GaAs buffer layer by molecu…
Resonant plasmon-assisted tunneling in a double quantum dot coupled to a quantum-Hall plasmon resonator
Chaojing Lin, Ko Futamata, Takafumi Akiho +2
Edge magnetoplasmon is an emergent chiral bosonic mode promising for studying electronic quantum optics. While the plasmon transport has been investigated with various techniques f…
Tunable tunnel coupling in a double quantum antidot with cotunneling via localized state
Tokuro Hata, Kazuhiro Sada, Tomoki Uchino +4
Controlling tunnel coupling between quantum antidots (QADs) in the quantum Hall (QH) regime is problematic. We propose and demonstrate a scheme for tunable tunnel coupling between…
Non-thermal Tomonaga-Luttinger liquid eventually emerging from hot electrons in the quantum Hall regime
Kotaro Suzuki, Tokuro Hata, Yuya Sato +3
Dynamics of integrable systems, such as Tomonaga-Luttinger (TL) liquids, is deterministic, and the absence of stochastic thermalization processes provides unique characteristics, s…
Coherent-Incoherent Crossover of Charge and Neutral Mode Transport as Evidence for the Disorder-Dominated Fractional Edge Phase
Masayuki Hashisaka, Takuya Ito, Takafumi Akiho +4
Couplings between topological edge channels open electronic phases possessing nontrivial eigenmodes far beyond the noninteracting-edge picture. However, inelastic scatterings mask…
Fast time-domain current measurement for quantum dot charge sensing using a homemade cryogenic transimpedance amplifier
Heorhii Bohuslavskyi, Masayuki Hashisaka, Takase Shimizu +3
We developed a high-speed and low-noise time-domain current measurement scheme using a homemade GaAs high-electron-mobility-transistor-based cryogenic transimpedance amplifier (TIA…
Non-uniform heat redistribution among multiple channels in the integer quantum Hall regime
Ryota Konuma, Chaojing Lin, Tokuro Hata +4
Heat transport in multiple quantum-Hall edge channels at Landau-level filling factor nu = 2, 4, and 8 is investigated with a quantum point contact as a heat generator and a quantum…
Impact of in-situ controlled disorder screening on fractional quantum Hall effects and composite-fermion transport
T. Akiho, K. Muraki
We examine the impact of random potential due to remote impurites (RIs) and its in-situ controlled screening on fractional quantum Hall effects (FQHEs) around Landau-level filling…
Gate tuning of fractional quantum Hall states in InAs two-dimensional electron gas
S. Komatsu, H. Irie, T. Akiho +3
We report the observation of fractional quantum Hall (FQH) effects in a two-dimensional electron gas (2DEG) confined to an InAs/AlGaSb quantum well, using a dual-gated Hall-bar dev…
Time-resolved investigation of plasmon mode along interface channels in integer and fractional quantum Hall regimes
Chaojing Lin, Masayuki Hashisaka, Takafumi Akiho +2
Quantum Hall (QH) edge channels appear not only along the edge of the electron gas but also along an interface between two QH regions with different filling factors. However, the f…
Andreev reflection of fractional quantum Hall quasiparticles
Masayuki Hashisaka, Thibaut Jonckheere, Takafumi Akiho +4
Electron correlation in a quantum many-body state appears as peculiar scattering behaviour at its boundary, symbolic of which is Andreev reflection at a metal-superconductor interf…
Cryogenic GaAs high-electron-mobility-transistor amplifier for current noise measurements
Sanghyun Lee, Masayuki Hashisaka, Takafumi Akiho +2
We show that a cryogenic amplifier composed of a homemade GaAs high-electron-mobility transistor (HEMT) is suitable for current-noise measurements in a mesoscopic device at dilutio…
Screening effects of superlattice doping on the mobility of GaAs two-dimensional electron system revealed by in-situ gate control
Takafumi Akiho, Koji Muraki
We investigate the screening effects of excess electrons in the doped layer on the mobility of a GaAs two-dimensional electron system (2DES) with a modern architecture using short-…
Quantized charge fractionalization at quantum Hall Y junctions in the disorder-dominated regime
Chaojing Lin, Masayuki Hashisaka, Takafumi Akiho +2
Fractionalization is a phenomenon where an elementary excitation partitions into several pieces. This picture explains non-trivial transport through a junction of one-dimensional e…
Energy gap tuning and gate-controlled topological phase transition in InAs/InGaSb composite quantum wells
H. Irie, T. Akiho, F. Couëdo +3
We report transport measurements of strained InAs/InGaSb composite quantum wells (CQWs) in the quantum spin Hall phase, focusing on the control of the energy gap thro…
Determination of -factor in InAs two-dimensional electron system by capacitance spectroscopy
Hiroshi Irie, Takafumi Akiho, Koji Muraki
We determine the effective -factor () of a two-dimensional electron gas (2DEG) using a new method based on capacitance spectroscopy. The capacitance-voltage profile of…
Impact of epitaxial strain on the topological-nontopological phase diagram and semimetallic behavior of InAs/GaSb composite quantum wells
H. Irie, T. Akiho, F. Couëdo +4
We study the influence of epitaxial strain on the electronic properties of InAs/GaSb composite quantum wells (CQWs), host structures for quantum spin Hall insulators, by transport…
Ballistic hot-electron transport in a quantum Hall edge channel defined by a double gate
Shunya Akiyama, Taichi Hirasawa, Yuya Sato +3
Ballistic transport of hot electrons in a quantum Hall edge channel is attractive for studying electronic analog of quantum optics, where the edge potential profile is an important…