Browsing by Author "Wang, Pengjie"

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    Depinning transition of bubble phases in a high Landau level
    (American Physical Society, 2015) Wang, Xuebin; Fu, Hailong; Du, Lingjie; Liu, Xiaoxue; Wang, Pengjie; Pfeiffer, L.N.; West, K.W.; Du, Rui-Rui; Lin, Xi
    In the higher Landau levels (N>0) a reentrant integer quantum Hall effect (RIQHE) state, which resides at fractional filling factors but exhibits integer Hall plateaus, has been previously observed and studied extensively. The nonlinear dynamics of the RIQHE were measured by microwave resonance, with the results consistent with an electronic bubble phase pinned by impurities. We have carried out depinning experiments on the N=2 bubble phases by using Corbino geometry, where depinning threshold values have been systematically measured as a function of magnetic fields and temperatures. Domain sizes and pinning potential of the bubble phases have been estimated from the nonlinear transport data.
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    Low-temperature conductivity of weakly interacting quantum spin Hall edges in strained-layer InAs/GaInSb
    (American Physical Society, 2017) Li, Tingxin; Wang, Pengjie; Sullivan, Gerard; Lin, Xi; Du, Rui-Rui
    We report low-temperature transport measurements in strainedﾠInAs/Ga0.68In0.32Sbﾠquantum wells, which supports time-reversal symmetry-protected helical edge states. The temperature and bias voltage dependence of the helical edge conductance for devices of various sizes are consistent with the theoretical expectation of a weakly interacting helical edge state. Moreover, we found that the magnetoresistance of the helical edge states is related to the edge interaction effect and the disorder strength.
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    Observation of a Helical Luttinger Liquid in InAs/GaSb Quantum Spin Hall Edges
    (American Physical Society, 2015) Li, Tingxin; Wang, Pengjie; Fu, Hailong; Du, Lingjie; Schreiber, Kate A.; Mu, Xiaoyang; Liu, Xiaoxue; Sullivan, Gerard; Csáthy, Gábor A.; Lin, Xi; Du, Rui-Rui
    We report on the observation of a helical Luttinger liquid in the edge of an InAs/GaSb quantum spin Hall insulator, which shows characteristic suppression of conductance at low temperature and low bias voltage. Moreover, the conductance shows power-law behavior as a function of temperature and bias voltage. The results underscore the strong electron-electron interaction effect in transport of InAs/GaSb edge states. Because of the fact that the Fermi velocity of the edge modes is controlled by gates, the Luttinger parameter can be fine tuned. Realization of a tunable Luttinger liquid offers a one-dimensional model system for future studies of predicted correlation effects.
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    Scaling properties of the plateau transitions in the two-dimensional hole gas system
    (American Physical Society, 2016) Wang, Xuebin; Liu, Haiwen; Zhu, Junbo; Shan, Pujia; Wang, Pengjie; Fu, Hailong; Du, Lingjie; Pfeiffer, L.N.; West, K.W.; Xie, X.C.; Du, Rui-Rui; Lin, Xi
    The behavior of phase coherence is studied in two-dimensional hole gas through the integer quantum Hall plateau-to-plateau transition. From the plateau transition as a function of temperature, scaling properties of multiple transitions are analyzed. Our results are in good agreement with the assumption of the zero-point fluctuations of the coherent holes, and support the intrinsic saturation of the coherence time at low temperature limit. The critical exponent p can also be determined under the scheme of the zero-point fluctuations. The similarity and difference in experimental observations between quantum Griffiths singularity and plateau transition is discussed. The spin-orbit coupling effect's influence on the plateau transition is explored by comparing the results from different transitions.