Vibrational Mode Lifetimes: New Insights

11:00 AM - 12:00 PM
Murray S. Daw, Clemson University, Clemson, S.C.
Materials Science and Technology Division
Materials Theory Group Seminar
Chemical and Materials Sciences Building (4100), Room J-302
Email: Valentino Cooper

We discuss a practical, new method for calculating vibrational mode lifetimes in
insulating solids. The approach is based on a recursion method analysis of the
Liouvillian. In practical terms, the calculation is accomplished by evaluating ensemble
averages of specific operators, meaning that the entire calculation is to be done with
Monte Carlo, given a means of calculating energies and forces. We discuss the results of
evaluating this method for both simple lattice models and more realistic interatomic
potentials. This technique should make possible the calculation lifetimes for even
complex materials and complex structures. Furthermore, the formalism leads to
interesting insights into how vibrational energy is thermalized.

[See Dickel & Daw, Comp Mat Sci, v47 p698 and v49 p445 (2010); Yang, Harrison,
Dickel, & Daw, Comp Mat Sci, v89 p12 (2014).]

The authors acknowledge support from the Dept. of Energy under grant DE-SC0008487.


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