Electronic structure, vibrational spectrum, and thermal properties of yttrium nitride: A first-principles study
Date of this Version
4-1-2011Citation
J. Appl. Phys. 109, 073720 (2011)
Abstract
Yttrium nitride (YN) is a promising semiconductor for use in metal/semiconductor superlattices for thermoelectric applications. We determine its electronic structure, vibrational spectrum, and thermal properties using first-principles density functional theory (DFT) based simulations with a generalized gradient approximation (GGA) of the exchange correlation energy. We employ GGA+U and GW approximations in our calculations to (a) improve the accuracy of the calculation of bandgaps and (b) determine specific features of its electronic structure relevant to transport properties, such as transverse (m(t)*) and longitudinal (m(1)*) conduction band effective mass. To evaluate consequences of forming alloys of YN with other materials to its electronic properties, we have determined the volume deformation potentials. Our results for phonons show a large longitudinal optical (LO) and transverse optical (TO) splitting at the Gamma point in the vibrational spectrum with a gap of 325 cm(-1) arising from long-range dipole-dipole interactions. We estimate temperature dependent lattice specific heat and lattice thermal conductivity based on Boltzmann transport theory to assess YN's potential for thermoelectric applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3561499]
Discipline(s)
Nanoscience and Nanotechnology
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Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 109, 073720 (2011) and may be found at http://dx.doi.org/10.1063/1.3561499. The following article has been submitted to/accepted by Journal of Applied Physics. Copyright (2011) Bivas Saha, Timothy D. Sands, and Umesh V. Waghmare. This article is distributed under a Creative Commons Attribution 3.0 Unported License.