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MM: Fachverband Metall- und Materialphysik

MM 30: Topical Session: Thermodynamics at the nano scale III - Novel experimental and theoretical approaches

MM 30.1: Talk

Tuesday, April 1, 2014, 15:45–16:00, BAR 205

Efficient evaluation of thermoelectric and electronic transport properties in a maximally-localized Wannier-function basis using the BoltzWann code — •Giovanni Pizzi¹, Dmitri Volja², Boris Kozinsky³, Marco Fornari⁴, and Nicola Marzari¹ — ¹Theory and Simulation of Materials, EPFL (CH) — ²Department of Materials Science and Engineering, MIT (USA) — ³Robert Bosch LCC Research and Technology Center, Cambridge (USA) — ⁴Dept. of Physics, Central Michigan University (USA)

The calculation of thermoelectric and electronic transport properties of extended systems requires extremely dense Brillouin-zone samplings together with the evaluation of band derivatives, that are however difficult to converge using standard finite-difference methods in systems where band crossings are present. We address both issues in our BoltzWann code [1] by adopting a maximally-localized Wannier function basis set. This allows both to interpolate the bands with very high accuracy thanks to the strong localization of the Wannier functions, and to calculate band derivatives analytically giving precise results also in the case of band crossings. BoltzWann then solves the semiclassical Boltzmann transport equations in the constant relaxation-time approximation to obtain transport properties (conductivities, Seebeck coefficient). We apply the code to some relevant systems like the CoSb₃ and CoGe_3/2S_3/2 skutterudites. BoltzWann is freely distributed as a module within the Wannier90 2.0 code [2].

[1] G. Pizzi et al., Comp. Phys. Comm. 185, 422 (2014)

[2] www.wannier.org