Giant polarization charge density at ScN/GaN interfaces

ORAL

Abstract


GaN is a wurtzite semiconductor that exhibits a large spontaneous polarization, while ScN is a semiconducting nitride that takes the nonpolar rocksalt crystal structure. Due to small lattice mismatch between ScN and GaN, it is possible to create a polar-nonpolar interface between the two materials.

Using density functional theory and the Berry-phase method, we examine the formal polarization of rocksalt ScN along the [111] direction, finding a polarization discontinuity of -1.358 Cm-2. We confirm this finding with explicit ScN/GaN supercell calculations. The polarization discontinuity causes a high-density electron gas to form on the N-polar GaN/ScN interface, and a hole gas to form on the Ga-polar interface, with carrier concentrations up to 8.5 x 1014 cm-2. The large polarization difference and low lattice mismatch make ScN a promising material for integration with III-nitride electronic and optoelectronic devices.

*This work is supported by AFOSR.

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Presenters

  • Nicholas Adamski

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

Authors

  • Nicholas Adamski

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

  • Cyrus Dreyer

    • Columbia University
    • Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York, 11794-3800, USA and Center for Computational Quantum Physics, Flatiron Institute, 162 5th
    • Department of Physics and Astronomy, Stony Brook University
    • State Univ of NY - Stony Brook
    • Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York, 11794-3800, USA, and Center for Computational Quantum Physics, Flatiron Institute, 162 5th

  • Chris Van de Walle

    • Materials Department, University of California, Santa Barbara
    • University of California, Santa Barbara