Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 94: Spin-Dependent Transport Phenomena I (organized by MA)

TT 94.5: Talk

Thursday, March 19, 2015, 10:30–10:45, H 0112

Higher dimensional Wannier functions for a description of multi-parameter ab initio Hamiltonians — •Jan-Philipp Hanke, Frank Freimuth, Stefan Blügel, and Yuriy Mokrousov — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Maximally localized Wannier functions (MLWFs) have become a widely applied tool in understanding the electronic structure [1]. Here, we present higher dimensional Wannier functions (HDWFs), which provide a minimal and accurate description of multi-parameter Hamiltonians H^{(k, λ)} carrying a dependence on the crystal momentum k and an additional periodic parameter λ. We derive a generalized interpolation scheme and emphasize the essential conceptual and computational simplifications in using the formalism for instance in the evaluation of linear response coefficients. The necessary machinery to construct HDWFs from ab initio is implemented within the full-potential linearized augmented plane-wave method (FLAPW) as realized in the FLEUR code [2]. We further apply our implementation to accurately interpolate the Hamiltonian of a one-dimensional magnetic chain of Mn atoms with spin-spiral texture in a composite space of Bloch and spin-spiral vectors, and thereby extract efficiently Heisenberg exchange constants.

Financial support by the HGF-YIG programme VH-NG-513 and SPP 1538 of DFG is gratefully acknowledged.

[1] N. Marzari and D. Vanderbilt, Phys. Rev. B 65, 12847 (1997).

[2] See http://www.flapw.de