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A. Kundu, F. Otte, J. Carrete, P. Erhart, W. Li, N. Mingo, G.K.H. Madsen:
"Effect of local chemistry and structure on thermal transport in doped GaAs";
Physical Review Materials, 3 (2019), 094602.

Using a first-principles approach, we analyze the impact of DX centers formed by S, Se, and Te dopant
atoms on the thermal conductivity of GaAs. Our results are in good agreement with experiments and unveil
the physics behind the drastically different effect of each kind of defect. We establish a causal chain linking
the electronic structure of the dopants to the thermal conductivity of the bulk solid, a macroscopic transport
coefficient. Specifically, the presence of lone pairs leads to the formation of structurally asymmetric DX centers
that cause resonant scattering of incident phonons. The effect of such resonances is magnified when they affect
the part of the spectrum most relevant for thermal transport. We show that, in the vibrational spectrum of the
perturbed system, they take the form of modes that are localized around the defect but still extended enough to
couple with incident phonons. Finally, we illustrate the connection between flat adjacent minima in the energy
landscape and resonant phonon scattering through detailed analyses of the energy landscape of the defective
structures.

http://dx.doi.org/10.1103/PhysRevMterials.3.094602