This paper reports on the results of ab initio spin-polarized GW calculations of quasiparticle properties, such as the spectral weight, the lifetime, the velocity, and the mean free path, for the FeCo ferromagnetic alloy and its components. The contribution of the localized d states to the above characteristics has been analyzed. The spin asymmetry of the properties of quasiparticle excitations, which is responsible for the spin filter effect observed in experiments, has been investigated. The contributions to the mean free path from the electron scattering processes, which are disregarded within the framework of the GW approximation, have been estimated from a comparison with experimental data.

This study was supported by the Department of Education of the Basque Government (grant no. 9/UPV 00206.215-13639/2001) and the Spanish Ministry of Science and Technology (grant no. FIS2004-06490-C03-01).

Peer reviewed