Electronic-structure of A Single Manganese Impurity In Aluminum

The electronic structure of a single manganese impurity in aluminum is studied using the discrete-variational local-spin-density-functional method with cluster models. The effects of size, geometry, and environment of clusters are considered. The results show that the dilute Al-Mn alloy is not a spin-fluctuation system and that the ground state of a single Mn in Al at T = 0 K is magnetic. The result of about a 3.2-mu-B local moment on the Mn impurity, which is partially compensated by an antiferromagnetic coupling to the Al conduction band, verifies the analysis of Cooper and Miljak. The value of the exchange splitting of the Mn 3s level is 2.92 eV, in excellent agreement with the experimental one (2.9 eV). In contrast with all previous computational results, but in agreement with results from recent x-ray-absorption spectra of Al-Mn alloys, we find a transfer of about one electron from the Mn impurity to the Al host.