Electronic Energy Bands of Nearly Free Electron Metallic Glasses An Application to Mg0.7Zn0.3 Amorphous Alloy

Abstract

AbstractA theory of electronic energy bands of nearly free electron like metallic glasses is presented by extending the l‐dependent pseudopotential method of Ziman. First an averaged Green's function is obtained for the substitutional alloy assuming average T‐matrix approximation (ATA). Then this Green's function is again averaged for the topological disorder by a Gaussian distribution of the lattice points in a manner similar to Kramer. The secular determinant obtained from the singularity condition of this doubly averaged Green's function is now complex and hence the energy‐eigenvalues obtained from this secular determinant are also complex. This theory is applied to the nearly free electron like metallic glass Mg0.7Zn0.3. From the complex energy bands the density of states and joint density of states for the optical absorption spectra are obtained as a function of the disorder parameter α. The results show that the Fermi energy falls at the minimum of the density of states for α = 0.05 confirming the observation of Nagel and Tauc. From this density of states the Pauli spin paramagnetic susceptibility is also calculated and the results show a temperature independence of this quantity completely in agreement with the experiment.