Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 56: Frontiers of Electronic Structure Theory: Many-Body Effects on the Nano-Scale IV

O 56.13: Talk

Wednesday, March 18, 2015, 18:15–18:30, MA 004

NanoDMFT: Full ab initio description of strong correlations in nanoscale devices — •David Jacob — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle

In order to obtain a full first-principles description of the correlated electronic structure and transport properties of nanoscale devices we combine the Coulomb-Hole-Screened-Exchange (COHSEX) approximation with Dynamical Mean-Field Theory (DMFT). While the former yields an effective mean-field description of the weakly correlated conduction electrons, the DMFT part accounts for the dynamic correlations originating e.g. from the strongly interacting 3d- or 4f-shells of transition metal atoms or from the molecular orbitals of weakly coupled molecular devices. The combination with COHSEX instead of Density Functional Theory (DFT) improves upon our NanoDMFT approach [1] in two important aspects: First, from the screened interaction W we can calculate the effective Coulomb interaction U for the strongly interacting electrons. Second, unlike in DFT+DMFT calculations the double-counting correction for COHSEX+DMFT is exactly known and straight-forward to calculate. Hence the two quantities which are essentially parameters in the DFT based approach can now be calculated ab initio so that it is now possible to actually predict e.g. the occurance of the Kondo effect in magnetic atoms and molecules on metal surfaces and attached to metallic leads.

[1] D. Jacob et al., PRL 103, 016803 (2009); D. Jacob et al., PRB 82, 195115 (2010); M. Karolak et al., PRL 107, 146604 (2011); D. Jacob et al., PRB 88, 134417 (2013)