The elastic constants Cij of bulk Bi2Te3 were calculated by density functional theory by different approximations. Computational results were validated by means of nanoindentation tests, performed along the directions parallel and perpendicular to the cleavage plane of Bi2Te3. The indentation modulus was estimated and compared with the experimental one. The generalized gradient Perdew-Burke-Ernzerhof approximation better reproduces experimental results in the direction perpendicular to the cleavage plane, whereas the occurrence of the nanobuckling in the direction parallel to the cleavage plane causes  iscrepancies between theoretical and experimental findings.

"Mechanical properties of Bi2Te3 topological insulator investigated by density functional theory and nanoindentation" C. Lamuta, D. Campi , A. Cupolillo , Z.S. Aliev, M.B. Babanly, E.V. Chulkov, A. Politano, L. Pagnotta . Scripta Materialia 121 (2016) 50–55