Insulator, conductor and commensurability: a topological approach
arXiv:cond-mat/0301338 · doi:10.1103/PhysRevLett.90.236401 10.1103/PhysRevLett.91.109901
Abstract
I discuss a topological relation of the conduction property of a many-particle system on a periodic lattice at zero temperature to the energy spectrum. When the particle number per unit cell is an irreducible fraction , an insulator must have low-lying states of energy in one dimension and of energy in two dimensions, where is the linear system size.
4 pages (no figures) in REVTEX; revised version with minor corrections