Calculation of the lattice thermal conductivity in GaAs-InAs alloys and comparison with experiment

The room-temperature lattice thermal conductivity of GaAs-InAs alloys is calculated and compared to recently measured thermal conductivity of GaAs dilutely alloyed with InAs [M. C. Ohmer, W. C. Mitchel, G. A. Graves, D. E. Holmes, H. Kuwamoto, and P. W. Yu, J. Appl. Phys. 64, 2775 (1988)] and with older data at higher concentrations. Our calculation considers both the normal and Umklapp anharmonic interaction, as well as mass differences and size distortions for the scattering by point defects. The results indicate that it is the size-distortion scattering which leads to a very abrupt decrease in the thermal conductivity for dilute alloys. The theory of Klemens and Callaway used in the present work is in semiquantitative agreement with experiments, consistent with both the experimental and theoretical uncertainties. Unlike previous calculations, we were able to reproduce a very sharp decline in the thermal conductivity upon alloying for very dilute alloys.