arXiv subjects

Peizhe Jia

Publications and source records attributed to Peizhe Jia.

3 recordsLinked to original sources

arXiv2026

Symmetry Breaking and Transition to Robust Excitonic Topological Order in InAs/GaSb Bilayers

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 Coulomb interactions play in symmetry breaking during topological transitions is a fundamental problem that has not been fully understood. Utilizing gated indium arsenide-gallium antimonide bilayers, we demonstrate that Coulomb interactions play a critical role in symmetry breaking and topological transitions. Whereas the quantum spin Hall insulator (QSHI) dominates the high-density regime, gating the system into the dilute regime enhances interlayer Coulomb interactions and leads to an emergent excitonic topological order (ETO) with spontaneous time-reversal-symmetry breaking. Moreover, applying a magnetic field drives a transition from the QSHI to the ETO accompanied by Coulomb-induced spin-rotation-symmetry breaking, which selects triplet electron-hole pairing in the lowest Landau levels. These results underscore an intricate interplay between symmetry and topology under Coulomb interactions in electron-hole bilayers.

cond-mat.mes-hall↗

arXiv2025

Hybridization Gap and Edge States in Strained-layer InAs/In0.5Ga0.5Sb Quantum Spin Hall Insulator

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 typical indium composition, x, ranges between 0.2 and 0.4. This enhancement prompts a critical question: to what extent can quantum wells (QWs) be strained while still preserving the fundamental QSHI phase? In this study, we demonstrate the controlled molecular beam epitaxial (MBE) growth of highly strained-layer QWs with an indium composition of x = 0.5. These structures possess a substantial compressive strain within the In0.5Ga0.5Sb QW. Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films, indicating coherent lattice structures and the absence of visible dislocations. Transport measurements further reveal that the QSHI phase in InAs/In0.5Ga0.5Sb QWs is robust and protected by time-reversal symmetry. Notably, the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field. This behavior is in agreement with the Z2 topological property predicted by the Bernevig-Hughes-Zhang (BHZ) model, confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain.

cond-mat.mtrl-sci↗

arXiv2022

Hydrodynamic charge transport in GaAs/AlGaAs ultrahigh-mobility two-dimensional electron gas

Viscous fluid in an ultrahigh-mobility two-dimensional electron gas (2DEG) in GaAs/AlGaAs quantum wells is systematically studied through measurements of negative magnetoresistance (NMR) and photoresistance under microwave radiation, and the data are analyzed according to recent theoretical work by e.g., Alekseev, Physical Review Letters 117,166601 (2016). Size-dependent and temperature dependent NMR are found to conform to the theoretical predictions. In particular, transport of 2DEG with relatively weak Coulomb interaction (interparticle interaction parameter r_s<1) manifests a crossover between viscous liquid and viscous gas. The size dependence of microwave induced resistance oscillations and that of the '2nd harmonic' peak indicate that 2DEG in a moderate magnetic field should be regarded as viscous fluid as well. Our results suggest that the hydrodynamic effects must be considered in order to understand semiclassical electronic transport in a clean 2DEG.

cond-mat.mes-hall↗