Gd 도핑된 비스무스 텔루라이드의 자기적 성질에 대한 제일원리 계산 연구

Abstract

Dept. of Nano Physics, Sookmyung Women’s University, Seoul 04310, Korea(Received 8 April 2016, Received in final form 18 April 2016, Accepted 19 April 2016)Determination of the structural, electronic, and magnetic properties of the magnetically doped bismuth-telluride alloys are drawing lots ofinterest in the fields of the thermoelectric application as well as the research on magnetic interaction and topological insulator. In this study,we performed the first-principles electronic structure calculations within the density functional theory for the Gd doped bismuth-telluridesin order to study its magnetic properties and magnetic phase stability. All-electron FLAPW (full-potential linearized augmented plane-wave) method is employed and the exchange correlation potentials of electrons are treated within the generalized gradient approximation.In order to describe the localized f-electrons of Gd properly, the Hubbard +U term and the spin-orbit coupling of the valence electrons areincluded in the second variational way. The results show that while the Gd bulk prefers a ferromagnetic phase, the total energy differencesbetween the ferromagnetic and the antiferromagnetic phases of the Gd doped bismuth-telluride alloys are about ~1 meV/Gd, indicating thatthe stable magnetic phase may be changed sensitively depending on the structural change such as defects or strains.Keywords : ferromagnetic, magnetic phase stability, thermoelectric, electronic structures calculation, spin-orbit coupling effect,magnetic doping