Thermal Conductivity and Large Isotope Effect in GaN from First Principles

Journal Article · Tue Aug 28 00:00:00 EDT 2012 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.109.095901· OSTI ID:1081204

Lindsay, L. ^[1]; Broido, D. A. ^[2]; Reinecke, T. L. ^[1]

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1. Naval Research Lab. (NRL), Washington, DC (United States)
2. Boston College, Chestnut Hill, MA (United States)

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.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
• Sponsoring Organization: USDOE
• DOE Contract Number: SC0001299; FG02-09ER46577
• OSTI ID: 1081204
• Journal Information: Physical Review Letters, Vol. 109, Issue 9; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; ISSN 0031-9007: PRLTAO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
solar (photovoltaic)
solar (thermal)
solid state lighting
phonons
thermal conductivity
thermoelectric
defects
mechanical behavior
charge transport
spin dynamics
materials and chemistry by design
optics
synthesis (novel materials)
synthesis (self-assembly)
synthesis (scalable processing)