Figure 1: Electron correlations in a triangular lattice.
From: Magnetic order in a frustrated two-dimensional atom lattice at a semiconductor surface

(a,b): Schematic presentation of the
-Sn/Si(111) surface and the isotropic triangular antiferromagnet in the case of a spiral AF order (
: electron-hopping parameters). (c) The single QP band E(k) in the Fermi liquid regime corresponding to our LDA surface band. (d) QP (heavy line) and shadow band (light line) induced by the Mott metal-insulator transition.