Article
Physics, Multidisciplinary
Woo Chang Chung, Julius de Hond, Jinggang Xiang, Enid Cruz-Colon, Wolfgang Ketterle
Summary: This study explores nonequilibrium spin dynamics in Mott insulator plateaus, observing a resonant effect in spin alignment as lattice depth changes when exchange coupling and on-site anisotropy are similar. The results are supported by many-body numerical simulations and analytical solutions of a two-site model. The research demonstrates the importance of a uniaxial single-ion anisotropy term in stabilizing magnetism for low-dimensional magnetic materials in optical lattices.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
Hiromitsu Takeuchi
Summary: The theoretical investigation of the phase diagram of lowest-energy vortices in the polar phase of spin-1 Bose-Einstein condensates reveals three types of vortices: elliptic AF-core vortices, axisymmetric F-core vortices, and N-core vortices. These vortices are named based on the local ordered state and have different stability conditions under various interactions. The phase transition between different types of vortices is studied, with continuous transitions observed between N-core vortex and the other two vortices, and a discontinuous transition between AF-core and F-core vortices.
Article
Chemistry, Multidisciplinary
Marek Korkusinski, Yasser Saleem, Amintor Dusko, Daniel Miravet, Pawel Hawrylak
Summary: We predict the existence of spontaneous spin and valley symmetry-broken states in a gated bilayer graphene quantum dot. By exact diagonalization of the many-body Hamiltonian, we find that the electron system undergoes phase transitions with increasing spin and valley polarizations as the Coulomb interaction strength increases. A phase diagram for N = 1-6 electrons is mapped out as a function of the Coulomb interaction strength.
Article
Materials Science, Multidisciplinary
A. A. Zvyagin, V. V. Slavin
Summary: This article discusses the stability of quantum spin-1 chain materials and their relationship to spin nematic ordering. The study found that spin nematic ordering is related to the spin subsystem's spin nematic order parameter, coupling to the elastic subsystem of the crystal, and interaction with ultracold bosons in a one-dimensional optical lattice.
Article
Materials Science, Multidisciplinary
O. A. Moreno Segura, K. Hallberg, A. A. Aligia
Summary: This study calculates the charge and spin gaps in the ionic Hubbard chain, considering density-dependent hopping with electron-hole symmetry. The disappearance of the charge (spin) gap indicates a quantum critical point in the charge (spin) sector. Between these critical points, the system behaves as a fully gapped spontaneously dimerized insulator. The study focuses on this region and explores the possibility of an adiabatic Thouless pump with alternating hopping, limited by the size of the gaps.
Article
Physics, Condensed Matter
Erhan Albayrak
Summary: The spin-1 XYZ model is analyzed using a mean-field approach on a honeycomb lattice. The study reveals that the model exhibits first- and second-order phase transitions, as well as critical and bicritical points, when considering the thermal behaviors of magnetizations under external magnetic fields in different dimensions.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
L. Banszerus, S. Moeller, C. Steiner, E. Icking, S. Trellenkamp, F. Lentz, K. Watanabe, T. Taniguchi, C. Volk, C. Stampfer
Summary: Understanding the coupling of electron spin with orbital degrees of freedom is crucial for applications in spin-based electronics and quantum computation. Recent experiments in bilayer graphene quantum dots have demonstrated the observation of spin-valley coupling and the effect of Kane-Mele type spin-orbit coupling in lifting the degeneracy of spin and valley states. These findings provide important insights for potential advancements in spin and spin-valley qubit operations.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Fei Gao, Jieming Sheng, Weijun Ren, Qiang Zhang, Xiaohua Luo, Ji Qi, Mengru Cong, Bing Li, Liusuo Wu, Zhidong Zhang
Summary: In this study, we investigated the magnetic structure and magnetocaloric effect of the ternary compound HoAl2Ge2. We found that HoAl2Ge2 exhibits an incommensurate spin density wave and has a special arrangement of magnetic moments, resulting in interesting physical phenomena and large magnetocaloric effects. We also examined the influence of magnetic field on the magnetocaloric effect and discussed the mechanism behind the observed effects.
Article
Chemistry, Multidisciplinary
Nicholas Dale, M. Iqbal Bakti Utama, Dongkyu Lee, Nicolas Leconte, Sihan Zhao, Kyunghoon Lee, Takashi Taniguchi, Kenji Watanabe, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Roland J. Koch, Jeil Jung, Feng Wang, Alessandra Lanzara
Summary: Using ARPES, the effects of many-body interactions and displacement field on the band structure of twisted bilayer graphene (tBG) devices at an intermediate (3 degrees) twist angle are studied. The observed renormalization of bands at the K points suggests the influence of moire models of the Hartree-Fock interaction. Evidence of correlation-enhanced inversion symmetry-breaking, shown as tunable gaps at the Dirac points, suggests a new approach to engineering band structure and symmetry-breaking phases in moire heterostructures.
Article
Physics, Multidisciplinary
E. Jurcisinova, M. Jurcisin
Summary: The influence of anisotropy generated by the competition between ferromagnetic and antiferromagnetic interactions on the magnetic and thermodynamic properties of a classical spin system on the octahedral lattice is investigated. A solvable Ising-like model is used to study the system, and the phase diagram and nature of phase transitions are determined. The model exhibits an intermediate phase that separates the ferromagnetic and antiferromagnetic phases, and different ground states and anomalous behavior are observed depending on the frustration parameter.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Yutaka Yamamoto, Masanori Ichioka, Hiroto Adachi
Summary: This study investigates the antiferromagnetic spin Seebeck effect across the spin-flop transition using numerical simulations. The results show that the sign reversal of the spin Seebeck effect is controlled by the exchange coupling at the interface and the spin dephasing in the metal layer.
Article
Physics, Multidisciplinary
A. Hijano, E. J. Rodriguez, D. Bercioux, D. Frustaglia
Summary: This work investigates the response of spin carriers to effective field textures in curved one-dimensional interferometric circuits, finding that the interplay between Rashba and Dresselhaus spin-orbit interactions and circuit geometry modifies the geometric characteristics of spinors, resulting in the localization of electronic wave function and suppression of quantum conductance.
COMMUNICATIONS PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Rajesh Tripathi, D. T. Adroja, C. Ritter, Shivani Sharma, Chongli Yang, A. D. Hillier, M. M. Koza, F. Demmel, A. Sundaresan, S. Langridge, Wataru Higemoto, Takashi U. Ito, A. M. Strydom, G. B. G. Stenning, A. Bhattacharyya, David Keen, H. C. Walker, R. S. Perry, Francis Pratt, Qimiao Si, T. Takabatake
Summary: In this study, the authors present experimental results on the CeRh1-xPdxSn compound to investigate its spin dynamics. The results show that the x=0.1 sample exhibits characteristics of a metallic spin-liquid ground state, while the x=0.2 sample shows spin-liquid behavior. The x=0.5 sample, on the other hand, exhibits a long-range antiferromagnetic ground state.
Article
Multidisciplinary Sciences
Sahar Satoori, Saeed Mahdavifar, Javad Vahedi
Summary: The ground state phase diagram of the dimerized spin-1/2 XX honeycomb model in the presence of a transverse magnetic field is investigated using numerical exact techniques. The quantum correlations, concurrence, and quantum discord among nearest-neighbor spins are analyzed, demonstrating their ability to capture the position of quantum critical points and provide information on long-ranged critical correlations. Additionally, a magnetic-entanglement behavior starting from the saturation field is addressed.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
Zhu -Xi Luo, Urban F. P. Seifert, Leon Balents
Summary: This study investigates the exotic phenomena arising from the relative twist of two layers of two-dimensional materials, particularly in a system with triangular lattices hosting Dirac quantum spin liquids. By using perturbation theory and self-consistency methods, it is found that the twisting angle can regulate the system's instability and the lattice constant of the magnetically ordered state.
Article
Multidisciplinary Sciences
Chaojing Lin, Masayuki Hashisaka, Takafumi Akiho, Koji Muraki, Toshimasa Fujisawa
Summary: Fractionalization is a phenomenon where an elementary excitation partitions into several pieces, explaining non-trivial transport through one-dimensional edge channels in quantum Hall states. By injecting charge q from a non-interaction region into an interacting and scattering region, a collective excitation with charge (1-r)q is formed by reflecting fractionalized charge rq, with fractionalization factors consistent with quantized values. The scheme allows for generating and transporting fractionalized charges along a well-defined path, demonstrating robust fractionalization in the hole-conjugate state at filling factor 2/3.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
M. Jo, P. Brasseur, A. Assouline, G. Fleury, H. S. Sim, K. Watanabe, T. Taniguchi, W. Dumnernpanich, P. Roche, D. C. Glattli, N. Kumada, F. D. Parmentier, P. Roulleau
Summary: Graphene serves as a promising platform for electron quantum optics, with the capability to tune electronic beam splitters and achieve nearly unity transmission. Comparisons with conventional semiconductor interferometers show graphene's robustness to universal processes driving quantum coherence.
PHYSICAL REVIEW LETTERS
(2021)
Review
Physics, Multidisciplinary
Toshimasa Fujisawa
Summary: Tomonaga-Luttinger liquids exhibit unique features that are not present in ordinary Fermi liquids. Recent advancements in measurement techniques have allowed the study of these unique characteristics in 1D quantum Hall edge channels. This review provides an overview of nonequilibrium dynamics in quantum-Hall Tomonaga-Luttinger liquids, including collective excitations, transport eigenmodes, and nonthermal steady states related to integrable models.
ANNALEN DER PHYSIK
(2022)
Article
Physics, Multidisciplinary
A. Assouline, M. Jo, P. Brasseur, K. Watanabe, T. Taniguchi, Th. Jolicoeur, D. C. Glattli, N. Kumada, P. Roche, F. D. Parmentier, P. Roulleau
Summary: Magnons can transfer magnetic moment or spin over long distances. In quantum Hall ferromagnets, it is predicted that spin and charge are entangled, resulting in magnons carrying an electric dipole moment. Evidence of this electric dipole moment is found in a graphene quantum Hall ferromagnet using a Mach-Zehnder interferometer, with the magnons affecting interferometer flux and interference pattern phase and visibility. The ability to couple spin degree of freedom to an electrostatic potential in quantum Hall ferromagnets could have implications for spintronics.
Article
Instruments & Instrumentation
Takase Shimizu, Masayuki Hashisaka, Heorhii Bohuslavskyi, Takafumi Akiho, Norio Kumada, Shingo Katsumoto, Koji Muraki
Summary: The article introduces a cryogenic transimpedance amplifier (TA) suitable for cross-correlation current-noise measurements, utilizing homemade high-electron-mobility transistors to achieve high resolution measurements, and demonstrating its advantages in measuring shot noise at quantum point contacts in a quantum Hall system.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Physics, Applied
Heorhii Bohuslavskyi, Masayuki Hashisaka, Takase Shimizu, Takafumi Akiho, Koji Muraki, Norio Kumada
Summary: We have developed a high-speed and low-noise time-domain current measurement scheme using a homemade cryogenic transimpedance amplifier (TIA), which is versatile for broad cryogenic current measurements, including semiconductor spin-qubit readout. The TIA has a broad frequency bandwidth and a low noise floor, and the performance can be adjusted by changing the feedback resistance.
APPLIED PHYSICS LETTERS
(2022)
Article
Optics
Katsumasa Yoshioka, Taro Wakamura, Masayuki Hashisaka, Kenji Watanabe, Takashi Taniguchi, Norio Kumada
Summary: Researchers have developed a gate-tunable graphene photodetector with a high bandwidth by using a resistive zinc oxide top gate. They found that the optical-to-electrical conversion in graphene is almost instantaneous and can be controlled by adjusting the Fermi level. This study bridges the gap between ultrafast optical science and device engineering, advancing the development of ultrafast graphene optoelectronic applications.
Article
Multidisciplinary Sciences
M. Jo, June-Young M. Lee, A. Assouline, P. Brasseur, K. Watanabe, T. Taniguchi, P. Roche, D. C. Glattli, N. Kumada, F. D. Parmentier, H-S Sim, P. Roulleau
Summary: Efforts have been made to understand and control decoherence in 2D electron systems, with graphene offering a unique opportunity to study unexplored regimes of electron interferometry. A graphene quantum Hall PN junction exhibits a remarkable crossover from exponential decay to algebraic decay of interference visibility as temperature decreases, a previously unobserved phenomenon in GaAs interferometers.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Kotaro Suzuki, Tokuro Hata, Yuya Sato, Takafumi Akiho, Koji Muraki, Toshimasa Fujisawa
Summary: The study demonstrates that non-thermal states can still emerge in Tomonaga-Luttinger (TL) liquids even when excited with extremely high-energy hot electrons in chiral quantum-Hall edge channels.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Multidisciplinary
H. Kamata, H. Irie, N. Kumada, K. Muraki
Summary: This paper presents a versatile on-chip time-resolved transport measurement scheme applicable to narrow-gap systems. The authors conducted experiments on noninverted InAs/InxGa1-xSb composite quantum wells and observed pulsed charge waveforms for both electrons and holes. They found that the group velocity of edge magnetoplasmon pulses is reduced and broadened in both the electron and hole regimes, suggesting the influence of charge puddles in the bulk.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Ryota Konuma, Chaojing Lin, Tokuro Hata, Taichi Hirasawa, Takafumi Akiho, Koji Muraki, Toshimasa Fujisawa
Summary: This study investigates heat transport in multiple quantum Hall edge channels at Landau-level filling factors v = 2, 4, and 8. The heat distribution among the channels remains highly nonuniform and can be explained by the plasmon eigenmodes. The heat transport can be controlled with a quantized heat valve, as evidenced by stepwise increases of heat current at the local thermometer.
Correction
Materials Science, Multidisciplinary
Toshimasa Fujisawa, Chaojing Lin
Article
Materials Science, Multidisciplinary
Toshimasa Fujisawa, Chaojing Lin
Summary: The paper introduces a model to explain the nontrivial modes observed in coupled quantum Hall edge channels. This model characterizes the Coulomb interaction and disorder-induced tunneling through coupling capacitances and tunneling conductances. The authors also propose transport experiments in frequency and time domains for determining eigenmodes using this model.
Article
Materials Science, Multidisciplinary
N. Kumada, N-H Tu, K-i Sasaki, T. Ota, M. Hashisaka, S. Sasaki, K. Onomitsu, K. Muraki
Article
Materials Science, Multidisciplinary
Masayuki Hashisaka, Koji Muraki, Toshimasa Fujisawa