Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 16: Theory: Metal-insulator transitions / Electronic structure calculations
HL 16.2: Vortrag
Montag, 11. März 2013, 15:45–16:00, H13
A functional renormalization group approach for treating interactions in disordered electron systems — •Christian Seiler1,2 and Ferdinand Evers1,2 — 1Institut für Nanotechnologie, Karlsruher Institut für Technologie, Karlsruhe, Germany — 2Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, Karlsruhe, Germany
We propose an approach to treat the effects of interactions in disordered electron systems on a numerical level. The idea is to solve the non-interacting disorder problem for a given disorder realization exactly. We then use the functional renormalization group method to introduce interactions on a perturbative level. In contrast to usual applications of the fRG, we formulate it in terms of the eigenfunctions of the disordered non-interacting Hamiltonian. Disorder averaging of physical quantities is performed as the final step. The main advantage of our approach is that we are able to treat disorder exactly from a numerical point of view. In fRG applications for clean systems the number of active degrees of freedom is reduced by projecting momenta near the Fermi surface to certain spots on this surface. Disordered systems do not lend themselves to such a treatment since momentum no longer is a good quantum number. Here, the challenge is to find another appropriate decimation technique. We devise, compare and discuss several candidates for such disorder-adapted decimation schemes.