Publications (36)
Insulator-to-metal Mott transition facilitated by lattice deformation in monolayer -RuCl on graphite
Xiaohu Zheng, Ogasawara Takuma, Huaxue Zhou +7
Creating heterostructures with graphene/graphite is a practical method for charge-doping -RuCl, but not sufficient to cause the insulator-to-metal transition. In this study…
Observation of Quantum Spin Hall States in InAs/GaSb Bilayers under Broken Time-Reversal Symmetry
Lingjie Du, Ivan Knez, Gerard Sullivan +1
Topological insulators (TIs) are a novel class of materials with nontrivial surface or edge states. Time-reversal symmetry (TRS) protected TIs are characterized by the Z2 topologic…
Hybridization Gap and Edge States in Strained-layer InAs/In0.5Ga0.5Sb Quantum Spin Hall Insulator
Wenfeng Zhang, Peizhe Jia, Wen-kai Lou +4
The hybridization gap in strained-layer InAs/InxGa1-xSb quantum spin Hall insulators (QSHIs) is significantly enhanced compared to binary InAs/GaSb QSHI structures, where the typic…
Stability of the 5/2 Fractional Quantum Hall State in a Corbino Disc Sample with In-plane Electric Fields
Zheyi Zhu, Pengjie Wang, Hailong Fu +4
Among the various geometries to study the fractional quantum Hall effect in two dimensional electron gas, the Corbino disc owns the advantage to probe the bulk properties directly.…
Stability of the bubble states in Corbino geometry under a tilted field
Pengjie Wang, Yijia Wu, Hua Chen +6
We measured the activation energy gap of the N = 2 bubble states using tilted-field technique in two GaAs/AlGaAs samples with Corbino geometry, and observed monotonically decreasin…
Resistive signature of excitonic coupling in an electron-hole double layer with a middle barrier
Xingjun Wu, Wenkai Lou, Kai Chang +2
We study the interlayer scattering mediated by long-range Coulomb interaction between electrons (density n) and holes (p) in a double-layer system. The gated device is made of InAs…
Gate-Tuned Spontaneous Exciton Insulator in Double-Quantum Wells
Lingjie Du, Wenkai Lou, Kai Chang +2
It was proposed that a dilute semimetal is unstable against the formation of an exciton insulator, however experimental confirmations have remained elusive. We investigate the orig…
Realization of independent contacts in barrier-separated InAs/GaSb quantum wells
Xingjun Wu, Jianhuan Wang, Miaoling Huang +2
InAs/GaSb double quantum wells (QWs) separated by a 100 Ã AlSb middle barrier are grown by molecular beam epitaxy. We report a nanofabrication technique that utilizes the surface F…
Observation of Superfluidity and Meissner Effect of Composite Bosons in GaAs Quantum Hall System
Yuanze Li, Renfei Wang, Jiahao Chen +7
The quantum Hall effect (QHE) is theoretically understood as a superfluid condensate of composite bosons (CBs) -- bound states of electrons and magnetic flux quanta. While dissipat…
Thermopower and Nernst measurements in a half-filled lowest Landau level
Xiaoxue Liu, Tingxin Li, Po Zhang +4
Motivated by recent proposal by Potter et al. [Phys. Rev. X 6, 031026 (2016)] concerning possible thermoelectric signatures of Dirac composite fermions, we perform a systematic exp…
Lessons from -RuCl3 for pursuing quantum spin liquid physics in atomically thin materials
Claudia Ojeda-Aristizabal, Xiaohu Zheng, Changsong Xu +20
Quantum spin liquids can arise from Kitaev magnetic interactions, and exhibit fractionalized excitations with the potential for a topological form of quantum computation. This revi…
Anisotropy of zero-resistance states in InN films under an in-plane magnetic filed
Xiaowei He, Yanhua Dai, Ivan Knez +3
We report low temperature current-voltage measurements on n-type InN films grown by molecular beam epitaxy. The zero-resistance state with a large critical current around 1 mA has…
Symmetry Breaking and Transition to Robust Excitonic Topological Order in InAs/GaSb Bilayers
Xinghao Wang, Wenfeng Zhang, Yujiang Dong +3
Symmetry and topology are fundamental concepts deeply intertwined in various fields of physics, especially in the studies of quantum phases of matter. The critical role that Coulom…
Anomalous Conductance Oscillations in the Hybridization Gap of InAs/GaSb Quantum Wells
Zhongdong Han, Tingxin Li, Long Zhang +2
We observe the magnetic oscillation of electric conductance in the two-dimensional InAs/GaSb quantum spin Hall insulator. Its insulating bulk origin is unambiguously demonstrated b…
Images of edge current in InAs/GaSb quantum wells
Eric M. Spanton, Katja C. Nowack, Lingjie Du +3
Quantum spin Hall devices with edges much longer than several microns do not display ballistic transport: that is, their measured conductances are much less than per edge.…
Composite Fermion States around 2D Hole Landau Level Filling Factor 3/2 in Tilted Magnetic Fields
Po Zhang, Ruiyuan Liu, Rui-Rui Du +2
Transport measurements under a tilted magnetic field were performed on a series of C-doped (001) AlGaAs/GaAs/AlGaAs two-dimensional hole samples. Due to a large g-factor, Zeeman en…
Perfect Andreev Reflection of Helical Edge Modes in InAs/GaSb Quantum Wells
Ivan Knez, Rui-Rui Du, Gerard Sullivan
We present an experimental study of inverted InAs/GaSb composite quantum wells in the hybridization regime and contacted by superconducting electrodes. A front gate is used to vary…
Laughlin pumping assisted by surface acoustic waves
Renfei Wang, Xiao Liu, Adbhut Gupta +8
The quantum Hall effect is a fascinating electrical transport phenomenon signified by precise quantization of Hall conductivity and vanishing longitudinal conducti…
Cryogen-free one hundred microKelvin refrigerator
Jiaojie Yan, Jianing Yao, Vladimir Shvarts +2
Temperature below 100 microKelvin is achieved in a customized cryogen-free dilution refrigerator with a copper-nuclear demagnetization stage. The lowest temperature of conduction e…
Hydrodynamic charge transport in GaAs/AlGaAs ultrahigh-mobility two-dimensional electron gas
Xinghao Wang, Peizhe Jia, Rui-Rui Du +3
Viscous fluid in an ultrahigh-mobility two-dimensional electron gas (2DEG) in GaAs/AlGaAs quantum wells is systematically studied through measurements of negative magnetoresistance…
Observation of a Helical Luttinger-Liquid in InAs/GaSb Quantum Spin Hall Edges
Tingxin Li, Pengjie Wang, Hailong Fu +8
We report on the observation of a helical Luttinger-liquid in the edge of InAs/GaSb quantum spin Hall insulator, which shows characteristic suppression of conductance at low temper…
Multi-Photon Transitions in Coupled Plasmon-Cyclotron Resonance Measured by Millimeter-Wave Reflection
Jie Zhang, Ruiyuan Liu, Rui-Rui Du +2
We construct a low-temperature microwave waveguide interferometer for measuring high-frequency properties of two-dimensional electron gases (2DEGs). Coupled plasmon-cyclotron reson…
Microwave Photocurrent from the Helical Edge state of InAs/GaInSb Bilayers
Jie Zhang, Tingxin Li, Rui-Rui Du +1
We measure microwave photocurrent in devices made from InAs/GaInSb bilayers where both insulating bulk state and conducting edge state were observed in the inverted-band regime, co…
Effective g-factors of carriers in inverted InAs/GaSb bilayers
Xiaoyang Mu, Gerard Sullivan, Rui-Rui Du
We perform tilt-field transport experiment on inverted InAs/GaSb which hosts quantum spin Hall insulator. By means of coincidence method, Landau level (LL) spectra of electron and…
Evidence for Helical Edge Modes in Inverted InAs/GaSb Quantum Wells
Ivan Knez, Rui-Rui Du, Gerard Sullivan
We present an experimental study of low temperature electronic transport in the hybridization gap of inverted InAs/GaSb composite quantum wells. Electrostatic gate is used to push…
Magneto-Induced Topological Phase Transition in Inverted InAs/GaSb Bilayers
Zhongdong Han, Tingxin Li, Long Zhang +1
We report a magneto-induced topological phase transition in inverted InAs/GaSb bilayers from a quantum spin Hall insulator to a normal insulator. We utilize a dual-gated Corbino de…
Superballistic flow of viscous electron fluid induced by microwave irradiation in quantum point contact
Xinghao Wang, Wenfeng Zhang, Rui-Rui Du +3
We measure the resistance oscillation of quantum point contact (QPC) under microwave (MW) radiation. What is different from the common resistance oscillation induced by edge magnet…
Mott Gap Softening Coinciding with Spin Correlations Collapse in a-RuCl3
Wei Yue, Xiaohu Zheng, Chongli Yang +2
The Mott insulator a-RuCl3, featuring the intertwined interplay of spin-orbit coupling (SOC) and Kitaev spin correlations, provides an unparalleled platform for probing quantum man…
Tuning Edge States in Strained-Layer InAs/GaInSb Quantum Spin Hall Insulators
Lingjie Du, Tingxin Li, Wenkai Lou +8
We report on a class of quantum spin Hall insulators (QSHIs) in strained-layer InAs/GaInSb quantum wells, in which the bulk gaps are enhanced by up to five folds as compared to the…
Interaction between Surface Acoustic Wave and Quantum Hall Effects
Xiao Liu, Mengmeng Wu, Renfei Wang +6
Surface Acoustic Wave (SAW) is a powerful technique for investigating quantum phases appearing in two-dimensional electron systems. The electrons respond to the piezoelectric field…
Tunneling spectroscopic signatures of charge doping and associated Mott transition in -RuCl in proximity to graphite
Xiaohu Zheng, Ke Jia, Junhai Ren +5
The layered Mott insulator -RuCl has been extensively studied as a potential Kitaev quantum spin liquid candidate. Here, by constructing heterostructures with graphite, w…
Incommensurate Charge Super-modulation and Hidden Dipole Order in Layered Kitaev Material -RuCl
Xiaohu Zheng, Zhengxin Liu, Cuiwei Zhang +5
The magnetism of Kitaev materials has been widely studied, but their charge properties and the coupling to other degrees of freedom are less known. Here we investigate the charge s…
Nonlinear transport of Wigner solid phase surrounding the two-flux composite fermion liquid
Yu-jiang Dong, Xinghao Wang, Jianmin Zheng +5
We have investigated the low temperature (T) transport properties of fractional quantum Hall (FQH) states in a high-mobility two-dimensional hole gas. According to the composite fe…
Simultaneous Measurements of Microwave Photoresistance and Cyclotron Reflection in the Multi-Photon Regime
Jie Zhang, Rui-Rui Du, L. N. Pfeiffer +1
We simultaneously measure photoresistance with electrical transport and plasmon-cyclotron resonance (PCR) using microwave reflection spectroscopy in high mobility GaAs/AlGaAs quant…
Low-Temperature Conductivity of Weakly Interacting Quantum Spin Hall Edges in Strained-Layer InAs/GaInSb
Tingxin Li, Pengjie Wang, Gerard Sullivan +2
We report low-temperature transport measurements in strained InAs/Ga0.68In0.32Sb quantum wells, which supports time-reversal symmetry-protected helical edge states. The temperature…
Excitonic topological order in imbalanced electron-hole bilayers
Rui Wang, Tigran A. Sedrakyan, Baigeng Wang +2
Correlation and frustration play essential roles in physics, giving rise to novel quantum phases [1-6]. A typical frustrated system is correlated bosons on moat bands, which could…