First-order Mott transition at zero temperature in two dimensions: Variational plaquette studyM. Balzer1, B. Kyung2, D. Sénéchal2, A.-M. S. Tremblay2 and M. Potthoff3
1 Institut für Theoretische Physik und Astrophysik, Universität Würzburg - Würzburg, Germany, EU
2 Département de physique and RQMP, Université de Sherbrooke - Québec, J1K 2R1 Canada
3 I. Institut für Theoretische Physik, Universität Hamburg - Hamburg, Germany, EU
received 19 August 2008; accepted in final form 27 November 2008; published January 2009
published online 7 January 2009
The nature of the metal-insulator Mott transition at zero temperature has been discussed for a number of years. Whether it occurs through a quantum critical point or through a first-order transition is expected to profoundly influence the nature of the finite-temperature phase diagram. In this paper, we study the zero temperature Mott transition in the two-dimensional Hubbard model on the square lattice with the variational cluster approximation. This takes into account the influence of antiferromagnetic short-range correlations. By contrast to single-site dynamical mean-field theory, the transition turns out to be first order even at zero temperature.
71.10.-w - Theories and models of many-electron systems.
71.30.+h - Metal-insulator transitions and other electronic transitions.
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