Electronic occupation functions for density-matrix tight-binding methods

We propose a method for including the fractional occupancy of electronic energy levels within a tight-binding density-matrix formalism. This method is based on successful techniques used in first-principles methods. Molecular-dynamics test simulations show that the density-matrix technique accurately reproduces the physics of a direct-diagonalization simulation using Fermi-Dirac occupancy. copyright 1996 The American Physical Society