Thermal expansion coefficients of Bi 2Se 3 and Sb 2Te 3 crystals from 10 K to 270 K

Abstract

Lattice constant of Bi 2Se 3 and Sb 2Te 3 crystals is determined by x-ray powder diffraction measurement in a wide temperature range. Linear thermal expansion coefficients (α) of the crystals are extracted, and considerable anisotropy between α ∥ and α ⊥ is observed. The low temperature values of α can be fit well by the Debye model, while an anomalous behavior at above 150 K is evidenced and explained. Grneisen parameters of the materials are also estimated at room temperature. © 2011 American Institute of Physics.