The Stark ladder density of states in a finite crystal

Abstract

The authors show that the density of states for an electron in a finite periodic lattice and an external electric field has a background of states proportional to Ed/2, where E and d are the energy and dimensionality of the system, respectively. This background is modulated by an asymptotically periodic structure with the Stark period that involves a fraction of order E-d/2 of the total number of states in each period. The structure is more pronounced in lower-dimensionality systems. Numerical results are included for a superlattice with a saw-tooth potential.