Contribution à l’investigation des comportements magnétiques et des structures électroniques d’un semiconducteur à base des impuretés magnétiques

Abstract

To produce innovative components in spintronics, we are now looking for ferromagnetic semiconductors at room temperature. The aim of this work is to study electronic structures, magnetic properties and trigger ferromagnetism and even improve the bandgap of PbSe. The properties of diluted magnetic semiconductors (DMS) type IVVI precisely Cr-doped PbSe are studied in detail. The calculation method used is FP-LAPW which is incorporated into the WIEN2K code within the general framework of density functional theory (DFT), using the generalized gradient density approximation (GGA). We have calculated the sp-d exchange couplings between the electrons of the conduction band or the holes of the valence band and the magnetic impurities. The topology of the band structure shows that our material has a half-metallic character. The efficiency of thermoelectric conversion focuses on a single parameter, the figure of merit ZT. We found that doping with a transition metal such as Chromium can also have a beneficial effect on thermal conductivity, and consequently on ZT. This makes our material among the best components for thermoelectric applications.