Mechanical and transport properties of BixSb2-xTe3 single quintuple layers

Abstract Bismuth antimony telluride (BST) is the state-of-the-art utilized thermoelectric alloy near room temperature. The BST single quintuple layers (QLs) are expected to accomplish two objectives simultaneously with both the increased power factor and the reduced thermal conductivity. In this work, the mechanical and transport properties of BST single QLs have been systematically explored. We have calculated the elastic modulus B 2 D , shear modulus G 2 D , sound velocity v m , Poisson’s ratio ν 2 D , and Debye temperature θ D for Bi x Sb 2 - x Te 3 ( 0 x 2 ) single QLs. Then the lattice thermal conductivity κ L is obtained by replacing the disordered crystal with an ordered one and treating the disorder as a perturbation based on the virtual crystal approximation. The κ L of the BST single QLs can decrease by at most 30%, compared to that of the virtual lattice. The low κ L (less than 1.2 Wm−1 K−1) at room temperature (300 K) will ensure the high thermoelectric performance for BST single QLs in a quite large concentration range.