Phase transitions in the two-dimensional Falicov-Kimball model on the triangular lattice

摘要

A recently developed numerical method, based on the modification of exact diagonalization calculations, is used to study the ground-state properties of the spinless Falicov-Kimball model on the triangular lattice. The phase diagram as well as the valence and metal-insulator transitions are analysed and compared with results of the conventional Falicov-Kimball model on the square lattice. It is shown that the different cluster geometry leads to various changes in basic characteristics of the model. In particular, the triangular lattice destroys the symmetry of the phase diagram as well as the valence transitions, and stabilizes the new types of spatial charge ordering - the axial stripes and the phase separated distributions of localized f-electrons. Studying the conducting properties of the Falicov-Kimball model on the triangular lattice, the Mott-Hubbard transition has been observed. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.