Accession Number:

ADA591492

Title:

Thermal Conductivity and Large Isotope Effect in GaN from First Principles

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

2012-08-28

Pagination or Media Count:

6.0

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.

Subject Categories:

  • Inorganic Chemistry
  • Physical Chemistry
  • Isotopes
  • Physics
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE