Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Matter at Low Temperature: Poster Session
TT 7.17: Poster
Montag, 25. Februar 2008, 14:00–18:00, Poster B
Competition between Interaction and Binary Disorder in Ultracold Fermions — •Denis Semmler1, Krzysztof Byczuk2, and Walter Hofstetter1 — 1Institut für Theoretische Physik, J. W. Goethe-Universität, D-60438 Frankfurt, Germany — 2Institute of Theoretical Physics, Warsaw University, ulica Hoża 69, PL-00-681, Poland
The interplay of interaction and disorder is of key importance for the electronic properties of realistic materials. Both effects can induce metal-insulator transitions [1]. More recently, optical lattices have given access to disordered fermionic quantum systems with a high degree of control. As interaction and disorder compete in a subtle way, obtaining new insight into this interplay is of large current interest.
We investigate a single band Anderson-Hubbard model by means of dynamical mean-field theory (DMFT), extended to include localization phenomena [2]. We consider binary disorder in the onsite energies, relevant e.g. for 2-species mixtures of cold gases. As the arithmetic averaged local density of states is not critical at the Anderson localization we calculate the geometric mean [2]. Our resulting phase diagram includes a disordered Fermi liquid, a Mott insulator at general filling, and an Anderson-localized phase.
[1] K. Byczuk, W. Hofstetter, D. Vollhardt, Phys. Rev. Lett. 94, 056404 (2005)
[2] V. Dobrosavljević, A. A. Pastor, B. K. Nikolić, Europhys. Lett. 62, 76 (2003)