Münster 1999 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 20: Metall-Isolator-Überg
änge
TT 20.10: Vortrag
Donnerstag, 25. März 1999, 18:00–18:15, F2
Mott-Hubbard transition in infinite dimensions — •F. Gebhard1 and R.M. Noack2 — 1FB Physik, Philipps-Universität Marburg, 35032 Marburg — 2Institut de Physique Théorique, Université Fribourg, CH-1700 Fribourg, Switzerland
Using the Random Dispersion Approximation [1] we calculate the zero-temperature quasiparticle weight and single-particle gap as a function of interaction strength, U, for the infinite-dimensional Hubbard model with a semi-elliptical density of states. We find that the quasiparticle weight goes to zero at the same critical value, Uc, at which the gap opens continuously. This picture of a continuous transition at a Uc of approximately the bandwidth is in disagreement with a previously proposed scenario of a discontinuous transition in which the gap jumps to a finite value at Uc,2 > Uc [2]. We quantitatively compare our results with those of a number of other methods in order to try to understand the origin of the disagreement.
[1] F. Gebhard, The Mott Metal-Insulator Transition, Springer Tracts in Modern Physics 137 (Springer, Berlin, 1997).
[2] A. Georges, G. Kotliar, W. Krauth, and M.J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996).