Thermal Conductivity and Large Isotope Effect in GaN from First Principles

Abstract

We present atomistic first principles results for the lattice thermal conductivity of GaN and compare them to those for GaP, GaAs, and GaSb. In GaN we find a large increase to the thermal conductivity with isotopic enrichment, ~65% at room temperature. We show that both the high thermal conductivity and its enhancement with isotopic enrichment in GaN arise from the weak coupling of heat-carrying acoustic phonons with optic phonons. This weak scattering results from stiff atomic bonds and the large Ga to N mass ratio, which give phonons high frequencies and also a pronounced energy gap between acoustic and optic phonons compared to other materials. Rigorous understanding of these features in GaN gives important insights into the interplay between intrinsic phonon-phonon scattering and isotopic scattering in a range of materials.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Aug 28, 2012
Accession Number
ADA591492

Entities

People

  • D. A. Broido
  • Lucas R. Lindsay
  • Thomas L. Reinecke

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Boltzmann Equation
  • Ceramic Materials
  • Computational Chemistry Methods
  • Conductivity
  • Crystal Lattice Vibrations
  • Crystal Lattices
  • Density Functional Theory
  • Energy Gaps
  • Experimental Data
  • Impurities
  • Materials
  • Molecular Dynamics
  • Point Defects
  • Power Electronics
  • Scattering
  • Semiconductors
  • Thermal Conductivity

Readers

  • Aquatic Ecology
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.
  • Thermal Physics or Thermal Science.