Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Focussed Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale II (organized by O)
TT 28.5: Vortrag
Montag, 31. März 2014, 17:15–17:30, TRE Ma
High Temperature Thermal Conductivity from First Principles — •Christian Carbogno1, Rampi Ramprasad2, and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — 2Chemical, Materials & Biomolecular Engineering, University of Connecticut, Storrs, USA
In spite of significant research efforts, a first principles determination of the thermal conductivity at high temperatures has remained elusive. Under such conditions, Boltzmann transport techniques [1] that include anharmonic effects only perturbatively become inaccurate or even inapplicable. In this work, we overcome this limitation by performing first-principles Green-Kubo simulations [2], in which all orders of anharmonicity are incorporated by the means of ab initio molecular dynamics. The thermal conductivity is then assessed from the auto-correlation function of the heat flux in thermodynamic equilibrium. We discuss the details of our implementation and the definition of our heat flux that is based on the virial theorem. We validate our approach by presenting calculations for ZrO2 that also showcase the importance of higher order anharmonic effects in materials with low thermal conductivities. Eventually, we discuss how our technique can be coupled to multi-scale models to achieve a computationally efficient and accurate description of the thermal conductivity at the nanoscale.
[1] D. A. Broido et al., Appl. Phys. Lett. 91, 231922 (2007).
[2] R. Kubo, M. Yokota, S. Nakajima, J. Phys. Soc. Jpn. 12, 1203 (1957).