Flat-Band Ferromagnetism as a Pauli-Correlated Percolation Problem

作者:Maksymenko M*; Honecker A; Moessner R; Richter J; Derzhko O
来源:Physical Review Letters, 2012, 109(9): 096404.
DOI:10.1103/PhysRevLett.109.096404

摘要

We investigate the location and nature of the para-ferro transition of interacting electrons in dispersionless bands using the example of the Hubbard model on the Tasaki lattice. This case can be analyzed as a geometric site-percolation problem where different configurations appear with nontrivial weights. We provide a complete exact solution for the one-dimensional case and develop a numerical algorithm for the two-dimensional case. In two dimensions the paramagnetic phase persists beyond the uncorrelated percolation point, and the grand-canonical transition is via a first-order jump to an unsaturated ferromagnetic phase.

  • 出版日期2012-8-28