Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Frontiers of Electronic-Structure Theory: Focus on the Interface Challenge VI (joint session O/CPP/DS/TT)
DS 18.4: Vortrag
Mittwoch, 3. April 2019, 15:45–16:00, H9
Many-body spectral functions from steady state density functional theory — •David Jacob1,2 and Stefan Kurth1,2,3 — 1Dpto. de Física de Materiales, Universidad del País Vasco UPV/EHU, San Sebastián, Spain — 2IKERBASQUE, Basque Foundation for Science, Bilbao, Spain — 3DIPC, San Sebastián, Spain
We present a scheme to extract the true many-body spectral function of an interacting many-electron system from an equilibrium density functional theory (DFT) calculation [1]. To this end we devise an ideal STM-like setup and employ the recently proposed steady-state DFT formalism (i-DFT) which allows to calculate the steady current through a nanoscopic region coupled to two biased electrodes [2]. In our setup one of the electrodes serves as a probe ("STM tip"). In the ideal STM limit of vanishing coupling to the tip, the system to be probed is in quasi-equilibrium with the "substrate" and the normalized differential conductance yields the exact equilibrium many-body spectral function. Moreover, from the i-DFT equations we derive an exact relationship which expresses the interacting spectral function in terms of the Kohn-Sham one. Making use of i-DFT xc functionals that capture Coulomb blockade as well as Kondo physics, the method yields spectral functions for Anderson impurity models in good agreement with NRG calculations. It is thus possible to calculate spectral functions of interacting many-electron systems at the cost of an equilibrium DFT calculation.
References: [1] D. Jacob and S. Kurth, Nano Lett. 18, 2086 (2018) [2] G. Stefanucci and S. Kurth, Nano Lett. 15, 8020 (2015)