Simple treatment of the anomalous interband dielectric constant of zero-gap semiconductors

Abstract

A simple treatment of the anomalous static and dynamic interband dielectric constant for zero-gap semiconductors is presented. It is based on an approximate form for the interband matrix element which can be inferred from the $f$ sum rule under a single-particle effective-mass approximation. The calculation encompasses as special cases, pure, doped, and strained crystals at finite temperature and in magnetic fields.