Temperature-dependent thermoelastic properties of GaSb and InSb semiconductors: Identification through ab initio DFT simulations

III-V semiconductors are extensively used in infrared sensor applications due to their superior structural and optical properties. Due to the extremes in the manifacturing and operating temperatures of the sensors, the knowledge of temperature-dependent elastic constants of these materials is of great importance. However, reliable measurements across a large range of temperatures prove difficult due to limitations of experimental setups. Density functional theory calculations present an affordable alternative. In this work, temperature-dependent elastic properties of InSb and GaSb are investigated using density functional theory within the quasiharmonic approximation. Calculated properties relevant for operation in a wide temperature range are presented including second order elastic constants, Young’s modulus ( E ), shear modulus ( μ ), Poisson’s ratio ν and the coefficient of thermal expansion ( α ). Our results are compared to available experimental values and good agreement is observed. • Elastic constants of GaSb and InSb compounds are obtained from ab initio DFT simulations inbetween 1K and ∼ 1000K. • Thermal constans of GaSb and InSb compounds are obtained from ab initio DFT simulations inbetween 1K and ∼ 1000K. • A closed form analytical free energy function expression is proposed for cubic crystals and the temperature variation of elastic constants are derived for GaSb and InSb according to the results obtained from DFT simulations.