Article
Materials Science, Multidisciplinary
Xiao Lei, Liang Zhou, Zhanyang Hao, Hongtao Liu, Shuo Yang, Haipeng Sun, Xiaozhou Ma, Chen Ma, Le Wang, Hai-Zhou Lu, Jia-Wei Mei, Jiannong Wang, Hongtao He
Summary: Shubnikov-de Hass oscillations are directly observed in undoped antiferromagnetic topological insulator MnBi2Te4. The oscillation period gradually decreases with increasing magnetic fields in the magnetic transition from canted antiferromagnetism to ferromagnetism and then saturates in high magnetic fields, indicating the field-induced evolution of the band structure. From the analysis of the high-field oscillations, a nontrivial Berry phase and a small effective mass are extracted. Furthermore, rotating the magnetization of MnBi2Te4 can lead to a splitting of the high-field oscillations, suggesting the enhanced asymmetry of the Weyl cones in tilted fields. Therefore, the observation of these magnetically tunable quantum oscillations clearly demonstrates the indispensable role of field in tuning the band structure or physical properties of MnBi2Te4.
Article
Chemistry, Physical
Do Wan Kim, Kyu Won Lee, Jae-Won Jang, Choel Eui Lee
Summary: The study observed quantum Hall effect-like plateaus in ZYA-grade HOPG, distinguishing between massless Dirac carriers and massive normal carriers. These plateaus were diminished after proton irradiation, demonstrating the potential of proton irradiation as a tool to manipulate quantum transport in HOPG by controlling its interlayer interaction.
Article
Quantum Science & Technology
Nand Kumar, Neha Wadehra, Ruchi Tomar, Shama, Sanjeev Kumar, Yogesh Singh, Sushanta Dattagupta, Suvankar Chakraverty
Summary: The study reveals the presence of the Rashba effect in the EuO-KTaO3 system, indicating the formation of Rashba spin-split bands with two Fermi surfaces and a Berry's phase, along with strong spin-orbit coupling. Additionally, the observation of the two-fold planar Hall effect and anisotropic magnetoresistance suggests a possible band diagram near the Fermi surface.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Physics, Condensed Matter
Longmeng Xu, Haoyu Niu, Yuming Bai, Haipeng Zhu, Songliu Yuan, Xiong He, Yibo Han, Lingxiao Zhao, Yang Yang, Zhengcai Xia, Qifeng Liang, Zhaoming Tian
Summary: The magnetotransport evidence and electronic structure calculations on SmAlSi compound reveal its nontrivial band topology. At low temperatures, SmAlSi exhibits large non-saturated magnetoresistance and distinct Shubnikov-de Haas oscillations. The analysis of SdH oscillations and calculated electronic band structures identify the nontrivial π Berry phases and small cyclotron mass of this compound.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Multidisciplinary
Le Duc Anh, Kengo Takase, Takahiro Chiba, Yohei Kota, Kosuke Takiguchi, Masaaki Tanaka
Summary: The epitaxial growth of high-quality alpha-Sn on InSb (001) is presented, showing unprecedentedly high quantum mobilities for both surface and bulk states. The research confirms that alpha-Sn grown on InSb (001) is a topological Dirac semimetal, demonstrating a crossover to a 2D topological insulator and phase transition to a trivial insulator with varying thickness. This work highlights alpha-Sn as a promising material for studying novel topological phases and for topological devices.
ADVANCED MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
K. Bolanos, S. de Castro, P. H. O. Rappl, E. Abramof, M. L. Peres
Summary: In this work, magnetotransport measurements were performed on an n-type single quantum well (QW) grown by molecular beam epitaxy, revealing metallic behavior and Shubnikov-de Haas oscillations under illumination, and insulating behavior in dark conditions. The observed oscillations were attributed to the multiple-valley Fermi surface of PbTe, with a phase characteristic of Dirac Fermions, in agreement with recent theoretical predictions of transport via topological surface states in PbTe films.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Chemistry, Multidisciplinary
Svetlana V. Gudina, Vladimir N. Neverov, Mikhail R. Popov, Konstantin V. Turutkin, Sergey M. Podgornykh, Nina G. Shelushinina, Mikhail V. Yakunin, Nikolay N. Mikhailov, Sergey A. Dvoretsky
Summary: By studying the Shubnikov-de-Haas oscillations, it is found that the Rashba spin-splitting in quantum wells with both a normal and inverted band structure is large and similar, with a value of 25-27 meV. This can be explained by the significant presence of p-type wave functions.
Article
Physics, Condensed Matter
Souvik Sasmal, Gourav Dwari, Bishal Baran Maity, Vikas Saini, A. Thamizhavel, Rajib Mondal
Summary: Anisotropic transport and quantum oscillations were studied on a high-quality CoSi single crystal grown by the Czochralski method. The dominant scattering mechanism was found to be electron-electron scattering, and the electrons were identified as the majority carriers with no electron-hole compensation. The effective masses and Dingle temperatures were calculated from the oscillation data.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Letter
Chemistry, Multidisciplinary
Daisy Q. Wang, Zeb Krix, Oleg P. Sushkov, Ian Farrer, David A. . Ritchie, Alexander R. . Hamilton, Oleh Klochan
Summary: By imposing an external periodic electrostatic potential, the electronic properties of the confined electrons in a quantum well can be different from those in the host semiconductor. In this study, we fabricated and investigated a tunable triangular artificial lattice on a GaAs/AlGaAs heterostructure, where the band structure and Fermi surface can be transformed by altering a gate bias. Magnetotransport measurements revealed multiple quantum oscillations and commensurability oscillations due to electron scattering from the artificial lattice. Increasing the modulation strength revealed new commensurability oscillations caused by electron scattering from the artificial Fermi surface and triangular lattice. These results demonstrate the ability to form artificial two-dimensional crystals with designer electronic properties using low disorder gate-tunable lateral superlattices.
Article
Nanoscience & Nanotechnology
Ying Zhang, Shasha Wang, Guojing Hu, Haoliang Huang, Bo Zheng, Yuehui Zhou, Yan Feng, Xiang Ma, Junfeng He, Yalin Lu, Meng Gu, Yu-Lun Chueh, Guorui Chen, Bin Xiang
Summary: This paper reports enhanced mobility of up to 540,000 cm2 V-1 s-1 in monolayer graphene sandwiched between two layers of a CrOCl insulator through a dielectric shielding effect. Additionally, Shubnikov-de Haas quantum oscillation is observed, with the amplitude linearly decreasing with increasing temperature, and it persists to a temperature as high as 100 K.
ACS APPLIED NANO MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Hiroshi Shimizu, Jiang Pu, Zheng Liu, Hong En Lim, Mina Maruyama, Yusuke Nakanishi, Shunichiro Ito, Iori Kikuchi, Takahiko Endo, Kazuhiro Yanagi, Yugo Oshima, Susumu Okada, Taishi Takenobu, Yasumitsu Miyata
Summary: This study reports the formation of a two-dimensional carrier gas in thin, ribbon-shaped bundles of WTe nanowires grown by chemical vapor deposition. The nanowires exhibit weak antilocalization and Shubnikov-de Haas oscillations at low temperatures, indicating the presence of a 2D carrier gas. The results highlight the potential of transition metal chalcogenide nanowires as building blocks for future electronic and energy-harvesting devices.
ACS APPLIED NANO MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
E. Tiras, S. Ardali, H. A. Firat, E. Arslan, E. Ozbay
Summary: The electronic transport properties of single-layer graphene on TiO2/Si substrate were studied, showing significant impact on the formation of 3D carriers and scattering mechanisms. The results indicate that different substrates lead to distinct changes in carrier densities and dominant scattering mechanisms.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Priyanath Mal, Bipul Das, Archana Lakhani, G. Bera, G. R. Turpu, C. V. Tomy, Pradip Das
Summary: This study reports the experimental realization of Dirac Fermions in 3D topological insulators by observing SdH oscillations with pi-Berry phase in PbBi2-xFexTe4, showing the existence of non-trivial topological surface states. The massless carriers with Fermi velocity around 10(5) ms(-1) depict their relativistic nature and the linear Dirac dispersion of topological surface states. The observed weak antilocalization and modified Hikami-Larkin-Nagaoka equation support the presence of 2D surface states with carriers moving around the Dirac point acquiring pi-Berry phase.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
Svetlana Gudina, Andrei S. Bogoliubskii, Anna S. Klepikova, Vladimir N. Neverov, Konstantin Turutkin, Sergey M. Podgornykh, Nina G. Shelushinina, Mikhail Yakunin, Nikolay N. Mikhailov, Sergey A. Dvoretsky
Summary: The longitudinal and Hall magnetoresistivity measurements were conducted in the Shubnikov-de Haas oscillation regime for HgCdTe/HgTe/HgCdTe heterostructures with a wide HgTe quantum well, revealing an anomalous phase shift of magneto-oscillations in the region of spin-unsplit peaks. This anomaly is attributed to the inverted spectrum in the size-quantized H1 subband of the HgTe quantum well. Comparisons were made with phase shift effects in monolayer graphene and HgMnTe quantum wells.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Minghui Gu, Ruixue Zhu, Xinxin Zhang, Zhenzhen Wang, Qichang An, Fang Yang, Xiaoran Liu, Peng Gao, Meng Meng, Jiandong Guo
Summary: By designing superlattices, the electron-electron correlation and spin-orbit coupling were found to cause a metal-nonmetal transition at 3d-Sd transition metal oxide interfaces.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Physics, Particles & Fields
Tigran A. Sedrakyan, Hrachya M. Babujian
Summary: In this study, a set of non-stationary quantum models are considered. It is shown that their dynamics can be studied by linking them to Knizhnik-Zamolodchikov (KZ) equations for correlation functions in conformal field theories. The boundary Wess-Zumino-Novikov-Witten model is specifically explored, where equations for correlators of primary fields are defined by an extension of KZ equations, revealing the connections to dynamical systems. As an example, an exact solution to a dynamical system that is a specific multi-level generalization of the two-level Landau-Zenner system, known as the Demkov-Osherov model, is provided to demonstrate the feasibility of the proposed method. The method can be used to study the nonequilibrium dynamics in various multi-level systems from the solution of the corresponding KZ equations.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Multidisciplinary Sciences
Rui Wang, Tigran A. Sedrakyan, Baigeng Wang, Lingjie Du, Rui-Rui Du
Summary: Correlation and frustration are important in physics, leading to new quantum phases. In this study, we observe the moat-band phenomena in shallowly inverted InAs/GaSb quantum wells, where we find an unconventional time-reversal-symmetry breaking excitonic ground state. We demonstrate the evolution from helical-like to chiral-like edge transport and explain our experimental observations using a moat band for excitons that results from density imbalance.
Article
Materials Science, Multidisciplinary
Rui Wang, Z. Y. Xie, Baigeng Wang, Tigran Sedrakyan
Summary: Topological phase transitions involving intrinsic topological orders cannot be described by conventional mean-field theories, but lattice Chern-Simons theory shows that traditional concepts can still play a crucial role in certain cases, while simplifying the transitions to effective mean-field theories based on fermionic degrees of freedom.
Article
Materials Science, Multidisciplinary
Ke Wang, T. A. Sedrakyan
Summary: Perpendicular magnetic field introduces an anomalous interaction correction to the static conductivity of doped graphene, leading to a proportional relationship between magnetoresistance and inverse temperature. This behavior originates from field-induced breaking of symmetry.
Article
Materials Science, Multidisciplinary
Ke Wang, M. E. Raikh, T. A. Sedrakyan
Summary: The presence of a weak perpendicular magnetic field in graphene breaks the chiral symmetry of each valley in the electron spectrum, leading to anomalous dependencies in the electron-electron interaction lifetime and magnetic field corrections to the thermodynamic characteristics. Experiments are discussed to explore the effects predicted by this symmetry breaking.
Article
Materials Science, Multidisciplinary
Ke Wang, M. E. Raikh, T. A. Sedrakyan
Summary: The study shows that the opposite chiralities of Dirac electrons in graphene significantly modify the Friedel oscillations, with a weak uniform magnetic field having an anomalous effect on the oscillations. This field-dependent contribution in a large spatial interval does not decay with distance, originating from a spin-dependent magnetic phase accumulated by the electron propagator.
Article
Optics
Chenan Wei, Tigran A. Sedrakyan
Summary: The SYK model's tractability at the large N limit allows for theoretical study of its chaotic behavior and holographic duality properties. The proposed setup provides a platform to realize the SYK model and investigate its exotic behavior using released fermion velocity distribution and many-body Loschmidt echo scheme.
Article
Materials Science, Multidisciplinary
Tigran A. Sedrakyan, Konstantin B. Efetov
Article
Materials Science, Multidisciplinary
Tigran Sedrakyan, Roderich Moessner, Alex Kamenev
Article
Materials Science, Multidisciplinary
Ke Wang, T. A. Sedrakyan
Article
Materials Science, Multidisciplinary
Saurabh Maiti, Tigran A. Sedrakyan
Article
Materials Science, Multidisciplinary
Saurabh Maiti, Tigran Sedrakyan
Article
Materials Science, Multidisciplinary
Rui Wang, Baigeng Wang, Tigran A. Sedrakyan
Article
Materials Science, Multidisciplinary
Tigran A. Sedrakyan, Konstantin B. Efetov
Article
Materials Science, Multidisciplinary
Tigran A. Sedrakyan, Victor M. Galitski, Alex Kamenev