Polarization-driven topological insulator transition in a GaN/InN/GaN quantum well

ORAL

Abstract

Topological insulators (TIs), a new state of quantum matter, have recently attracted significant attention, both for their fundamental research interest and for their potential device applications. Although many families of TI materials have been found, the realization of TI in conventional semiconductors remains elusive, mainly due to their sizable gaps and small spin-orbit interactions (SOI). Based on advanced first-principles calculations combined with an effective low-energy k$\cdot$p Hamiltonian, we show that the intrinsic polarization of materials can be utilized to simultaneously reduce the energy gap and enhance the SOI, driving the system to a TI state. The proposed system consists of ultrathin InN layers embedded into GaN, a layer structure that is experimentally achievable. We found that the TI transition happens at GaN/InN/GaN quantum well with 3 to 4 InN atomic layers. Since polarization fields occur in many materials, a similar mechanism may apply to other systems as well. Our approach may pave the way toward integrating controllable TIs with conventional semiconductor devices.

*We thank grants: DOE-BES (Grant No. DE-SC0001009); NSF- DGE0801627; MRSEC program (NSF- DMR1121053); NSF DMR-0906805; China 973-program 2011CB922204 and China NSF 10934007.

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Authors

  • M.S. Miao

    • Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA

  • Qimin Yan

    • University of California at Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA
    • Materials Department, University of California at Santa Barbara

  • Chris Van de Walle

    • University of California at Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials Department, University of California Santa Barbara
    • University of California, Santa Barbara
    • University of California, Santa Barbara Materials Department
    • University of California Santa Barbara
    • Materials department and materials Research Lab, University of California Santa Barbara, California 93106-5050, USA
    • Materials Department, University of California at Santa Barbara

  • W.K. Lou

    • SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China

  • L.L. Li

    • SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China

  • K. Chang

    • SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, P. R. China