Talks and Poster Presentations (without Proceedings-Entry):
M. Arrigoni, J. Carrete, N. Mingo, G.K.H. Madsen:
"Role of force-constant disorder in the lattice thermal conductivity of semiconductor alloys: a first-principles study";
Talk: European Materials Research Society Spring Meeting 2018,
Random semiconductor alloys find application in several technological devices, such as light emitting diodes, quantum cascade lasers, multi-junction concentrator solar cells and high-temperature thermoelectrics. Thermal management plays an essential role in these systems and methods able to predict their thermal conductivity are increasingly sought. The combination of first-principles calculations with the Boltzmann transport equation has proved to be an efficient and accurate method in determining the lattice thermal conductivity of semiconductor single crystals. The approaches commonly employed for their alloys consider the disordered mixture as a mass perturbation affecting an underlying non-structural effective medium. While such approximation shows a good predictive power for a limited set of compounds, it fails for general III-V semiconductor alloys. This failure is not surprising as several experimental studies have shown that these materials are characterized by a complex atomic-scale structure. In this contribution, taking In1-xGaxAs as a model material, we analyze the shortcomings of such models and show that a considerable improvement can be achieved by employing a structural description of the alloy and including the effects of local disorder through the introduction of a force-constant perturbation. We then present a first-principles method [arXiv:1712.02577] which implements these ingredients and finally demonstrate its ability to accurately predict the thermal conductivity of general semiconductor alloys.
Created from the Publication Database of the Vienna University of Technology.