Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 38: Theory of strongly correlated systems
MA 38.4: Vortrag
Donnerstag, 15. März 2018, 10:30–10:45, H 0110
Electronic entropy in finite-temperature Green’s-function calculations — •Ilja Turek1,2, Josef Kudrnovsky3, and Vaclav Drchal3 — 1Institute of Physics of Materials, Czech Acad. Sci., Brno, Czech Rep. — 2Charles University, Faculty of Mathematics and Physics, Prague, Czech Rep. — 3Institute of Physics, Czech Acad. Sci., Prague, Czech Rep.
Reliable evaluation of thermodynamic potentials of metallic materials and itinerant magnets at finite temperatures (free energy, grand-canonical potential) requires investigation of systems with perturbed translation invariance. For this purpose, Green’s-function techniques are often applied, which use a complex energy variable and integrations over contours in the complex plane. However, for quantities related to the electronic entropy, the branch cut of the complex logarithmic function prevents standard deformations of the integration paths. We have derived and numerically implemented an alternative expression for the electronic entropy, which is not affected by the multi-valued nature of the complex logarithm. In this contribution, the developed theoretical formalism will be presented and its efficiency and accuracy in selected cases (on model and ab initio levels) will be discussed.