Structural characterization of Bi2Te3 and Sb2Te3 as a Function of Temperature Using Neutron Powder Diffraction (NPD) and Extended X-ray Absorption Fine Structure (EXAFS) Techniques
Winnie Wong-Ng, Azzam Mansour, Qingzhen Huang, Weihua Tang, Jeff Sharp, Alan Thompson
The structure of Bi2Te3 (Seebeck coefficient Standard Reference Material (SRM™ 3451)), and the related phase Sb2Te3 have been characterized as a function of temperature using the neutron powder diffraction (NPD) and the extended X-ray absorption fine structure (EXAFS) techniques. The neutron structural studies were carried out from 20 K to 300K for Bi2Te3 and from 10K to 298 K for Sb2Te3. The EXAFS technique for studying the local structure of the two compounds was conducted from 19K to 298K. Bi2Te3 and Sb2Te3 are isostructural, with a space group of R m. The structure consists of repeated quintuple layers of atoms, Te2-M-Te1-M-Te2 (where M=Bi or Sb) stacking along the c-axis of the unit cell. EXAFS was used to examine the bond distances and static and thermal disorder for the first three shells of Bi2Te3 and Sb2Te3 as a function of temperature. The Debye and Einstein temperatures for the first three shells of Bi2Te3 are lower than those for Sb2Te3. The Einstein temperature for the third shell is consistent with a soft phonon mode in both Bi2Te3 and Sb2Te3, which may lead to lower thermal conduction.
, Mansour, A.
, Huang, Q.
, Tang, W.
, Sharp, J.
and Thompson, A.
Structural characterization of Bi2Te3 and Sb2Te3 as a Function of Temperature Using Neutron Powder Diffraction (NPD) and Extended X-ray Absorption Fine Structure (EXAFS) Techniques, Journal of Applied Physics, [online], https://doi.org/10.1063/1.4892441
(Accessed February 27, 2024)