TB-LMTO method for an embedded cluster

Abstract

A method aimed at calculation of the electronic structure of an atomic cluster embedded either in an ideal crystal or in an effective medium representing a random alloy is developed on the basis of the TB-LMTO scheme. We discuss the construction of embedding potentials, the correct treatment of electrostatic interactions of the cluster with the surrounding medium, and the calculation of cluster energies. We derive the corrections to the band energy of a cluster. The method makes it possible to determine the electronic structure (charge distribution, local densities of states) and magnetic properties of the cluster and to extract impurity formation energies, and effective interactions between atoms and between magnetic moments. As an illustration, the method is applied to studies of magnetism of non-magnetic impurities in oxides, to calculations of the formation energies for impurities in a metal host and to the determination of the parameters of the Bruno-Zingales-Wang model of charge transfer and screening in metallic alloys.

Keywords:

• linear muffin-tin orbital method
• embedded cluster
• random alloy
• impurity formation energy
• interatomic interactions
• exchange interactions
• charge transfer
• ab-initio
• alloys

Acknowledgements

This research was carried out within the project AVOZ10100520 of the Academy of Sciences of the Czech Republic. Financial support was provided by the Grant Agency of the Academy of Sciences of the Czech Republic (Project A100100616).