Lattice relaxation around positive muon in copper

Abstract

A model to study the local structure and geometry of condensed matter was applied to the lattice dilatation of Cu if a μ⁺ is implanted interstitially. The model system consists of a finite cluster of atoms embedded in the spherically symmetric part of the potential of the rest of the material.

The calculations were calibrated with crystalline Cu using a cluster of 6 atoms and 0, 6 or a practical infinite number of layers around this central cluster. It is found that 6 layers are enough to deseribe the boundary conditions that the material imposes to the selected central cluster.

Afterwards it was applied to a cluster of a central μ⁺ and 6 octahedrally disposed Cu. The equilibrium geometries, electronic configurations, electronic densities of states are presented and compared with μSR.