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.
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Presenters
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Nicholas Adamski
Department of Electrical and Computer Engineering, University of California, Santa Barbara
Authors
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Nicholas Adamski
Department of Electrical and Computer Engineering, University of California, Santa Barbara
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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
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Chris Van de Walle
Materials Department, University of California, Santa Barbara, University of California, Santa Barbara