Programme

P.67 -- Poster, VCTP-45

Date: Wednesday, 14 October 2020

Time: 08:30 - 10:00

Online presentation

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

Tran Van Quang1 and Miyoung Kim2

1 Department of Physics, University of Transport and Communications, Hanoi, Vietnam 2Department of Applied Physics, Sookmyung Women’s University, Seoul 04310, Republic of Korea

Rare earth doped Bi2Te3 reveals many exotic magnetic properties in host materials which is promising for the functional-material applications such as thermoelectricity and spintronics. In this work, within the density functional theory, we carried out first-principles electronic structure calculation to examine ground states and thermoelectric properties of Gd doped bismuth telluride. The strong correlation and spin-orbital coupling effects were found to be important to describe the electronic structure of the alloy. Results show that Gd substituted alloy is ferromagnetic with the magnetic moment of 7µB which purely comes from f-states of Gd atoms. Interaction between the valence electrons produces Gd1/3Bi5/3Te3 to be semimetallic, which drastically reduces the Seebeck coefficient. To substantiate this point, we calculated the transport coefficients, i.e. the Seebeck coefficient, the electrical conductivity and the thermoelectric power factor by utilizing the solution of Boltzmann transport equation in a constant relaxation-time approximation. The bipolar conduction effect is responsible for a drastic reduction of the Seebeck coefficient thereby the power factor. We pointed out that optimizing the carrier concentration was a method to feasibly improve the power factor thereby the thermoelectric performance of Gd1/3Bi5/3Te3.

Presenter: Tran Van Quang

Presentation file: