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TT: Fachverband Tiefe Temperaturen

TT 9: Correlated Electrons: Metal-Insulator Transition 1

TT 9.4: Vortrag

Montag, 23. März 2009, 14:45–15:00, HSZ 03

LDA+DMFT study of Ca₂RuO₄ and Sr₂RuO₄ using the full on-site Coulomb interaction — •Evgeny Gorelov¹, Eva Pavarini¹, and Alexander I. Lichtenstein² — ¹Forschungszentrum Jülich, IFF, 52425 Jülich, Germany — ²Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany

The Ca_2−xSr_xRuO₄ layered ruthenates display a complex phase diagram. Whereas Sr₂RuO₄ is a correlated metal, the progressive substitution Sr with Ca leads to a number of structural phase changes. Finally, Ca₂RuO₄ exhibits Mott transition at T≈350 K [1].

In this work we calculate the photoemission spectra of Sr₂RuO₄ [2] and study the temperature-induced Mott transition in Ca₂RuO₄ [3].

As a method we use the LDA+DMFT technique. First we construct a material-specific NMTO Wannier basis for the partially filled 4d t_2g bands and the corresponding three-band t_2g Hubbard Hamiltonian. Then we solve this model within the DMFT approximation retaining the full self-energy matrix and using the Continuous Time QMC impurity solver [4]. This solver allow us to analyze the role played by the spin-flip terms of the on-site Coulomb vertex.

[1] O. Friedt, M. Braden, G. Andre, P. Adelmann, S. Nakatsuji, Y. Maeno, Phys. Rev. B 63, 174432 (2001).

[2] E. Gorelov, A. N. Rubtsov, A.V. Lukoyanov, V.I. Anisimov and A. I. Lichtenstein, to be published.

[3] E. Gorelov and E. Pavarini, to be published.

[4] A. N. Rubtsov, V. V. Savkin, and A. I. Lichtenstein, Phys. Rev. B 72, 035122 (2005).