Relationship between statistical shift of the Fermi level and activation energy of conductivity in phase-change materials

Abstract

The non-Arrhenius behaviour of conductivity of phase-change materials is analysed in terms of the statistical shift of Fermi level. To show this connection, a simplified model for the density of states in a phase-change material is proposed to simulate the temperature dependence of the Fermi level. Comparison of the temperature dependence of conductivity of Ge2Sb2Te5 with the simulation results allowed estimating the position of defect levels in the bandgap.