Program

O.20 -- Oral, NCTP-41

Date: Wednesday, 3 August 2016

Time: 14h20 - 14h40

Thermoelectric and magnetic properties of gadolinium doped bismuth telluride: first-principles investigation

Tran Van Quang (1,2), Miyoung Kim (3)

(1) Department of Physics, University of Transport and Communications; (2) Institute of Research and Development, Duy Tan University; (3) Dept. of Nano Physics, Sookmyung Women’s University, Seoul 04310, Korea.

Bismuth telluride with doped magnetic elements have been great of interest in the years due to its potential application as thermoelectrical materials and the unique electronic structures related to the topological insulator. Especially, rare earth doping reveals many exotic magnetic property change in host materials. In this work, within the density functional theory, we perform first-principles electronic structure calculation by employing the all-electron full-potential linearized augmented planewave (FLAPW) method [1] to examine magnetic properties and thermoelectric properties of Gd doped bismuth telluride. Results show that Gd substituted alloy is ferromagnetic with the magnetic moment of 7$\mu B$ which purely comes from f-states of Gd atoms. The strong correlation and spin-orbital coupling effects are crucial to describe the electronic structure of the alloy. Interaction between the valence electrons produces semimetallic Gd-Bi2Te3, which enhances the electrical conductivity, but decrease the Seebeck coefficient on the other hand. To substantiate this point, we calculate the Seebeck coefficient, the electrical conductivity, and the thermoelectric power factor by utilizing the FLAPW wave-functions and the solution of Boltzmann transport equation in a constant relaxation-time approximation. [1] E. Wimmer, H. Krakauer, M. Weinert, and A. J. Freeman, Phys. Rev. B 24, 864 (1981).

Presenter: Tran Van Quang