Etude par la FPLAPW des propriétés structurales et électroniques des Thulium pnictogene TmX (X=N, P, As, Sb et Bi)

Abstract

A basic calculation has been carried out on the structural, electronic and magnetic properties of the binary compounds of thulium TmX (X= N, P, As, Sb, Bi) in the two forms NaCl and CsCl. The method of linearized augmented plane waves at a total potential (FA-LAPW) based on the density functional theory DFT was used in order to understand the characteristics of TmX. The exchange and correlation potential was treated by the gradient approximation generalizes GGA and mBJ-GGA. The results obtained showed that the most stable phase for the TmX compounds is the NaCl phase, and these materials undergo a phase transition towards the CsCl structure. The study of electronic properties has shown that TmX are metals in the spin-dn direction by the use of GGA and mBJ-GGA. While for the spin-up direction, TmN and TmSb were found to be almost half-metal with the use of GGA and half-metal with mBJ-GGA. TmP was found metal with GGA and semi-metal with mBJ-GGA. However, TmAs was proven to be a metal with the use of GGA and nearly half-metal with mBJ-GGA. The TmBi showed different behavior, the band structure of spin-up and spin-dn was similar, which explains the TmBi is a non-magnetic material and it is a metal.