Mapping the topological-to-normal insulator phase transition in InAs/GaSb bilayers by heterostructure variation

ORAL

Abstract

When 2D electron and hole subbands in InAs/GaSb bilayers are tuned to the inverted regime the system is predicted to exhibit an insulating bulk and counter propagating helical 1D edge states. This work presents a dual-gate mapping of the topological-to-normal insulator phase transition for several InAs/GaSb bilayers wherein the InAs and GaSb layer thicknesses are varied. In-plane and out-of-plane magnetotransport experiments reveal the effect of heterostructure geometry on the magnitudes of the longitudinal and Hall magnetoresistances and on the shape and temperature dependence of the gate-tuned resistance map in the vicinity of the phase transition.

*This work was supported by Microsoft Research

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Authors

  • Borzoyeh Shojaei

    • Materials Department, University of California at Santa Barbara

  • Anthony P. McFadden

    • ECE Department, University of California - Santa Barbara
    • Department of Electrical and Computer Engineering, University of California at Santa Barbara
    • Department of Electrical and Computer Engineering, Univ of California, Santa Barbara

  • Joon Sue Lee

    • California NanoSystems Institute
    • Dept. of Physics, Penn State Univ.

  • Mihir Pendaharkar

    • Department of Electrical and Computer Engineering, University of California at Santa Barbara
    • Department of Electrical and Computer Engineering, Univ of California, Santa Barbara

  • Chris Palmstrom

    • California NanoSystems Institute, University of California Santa Barbara
    • Materials Department, Department of Electrical and Computer Engineering, University of California at Santa Barbara
    • Materials Department, University of California-Santa Barbara, Santa Barbara, California 93106, USA
    • Electrical and Computer Engineering Department & Materials Department, University of California Santa Barbara
    • Materials Department and Department of Electrical and Computer Engineering, Univ of California, Santa Barbara
    • Materials Department, University of California, Santa Barbara