Etude du premier principe de la coexistence de la supraconductivité et le magnétisme à travers les mécanismes de liaisons dans les pnictures de Fer

Abstract

In this work, we have used the FP-L /APW+lo method to study the electronic structure of superconductors LnFePO (Ln=Ce, Pr, Nd, Sm et Gd) Compounds CeFePO a using different approaches: LSDA, LSDA+U. First, we have evaluated the most stable magnetic configurations of both LaFePO and SmFePO compounds: nonmagnetic state and the magnetic order [Sm: AFM, Fe: AFM_stripe] for LaFePO and SmFePO compounds respectively. These results are in excellent agreement with the experimental observations. Electronic and magnetic properties are determinate and discussed. The electronic structures of the LnFePO compounds (Ln = Ce, Pr, Nd, Sm and Gd) belonging to the same family: 1111, were compared. In order to highlight the general trends appearing in the electronic properties common to these superconducting compounds iron based. We have pointed that the variation of the rare earth atom leads to a change in ferro-orbitals, which make up the Fermi surface, directly lead to the increase of the superconducting temperature.