Electronic and transport properties of Mg2Si under isotropic strains

• Thermoelectric properties of isotropically constrained Mg2Si have been calculated.
• Density-functional theory and Boltzmann theory calculations have been performed.
• Mg2Si under tensile strain shows best performances for n-type doping.
• Seebeck coefficient is best for Mg2Si under 2% tensile strain.
• Power factor improves by almost 100% w.r.t. unstrained Mg2Si.

Density functional theory and Boltzmann theory calculations of the electronic and thermoelectric properties of Mg2Si subjected to isotropic strains have been performed. The electrical conductivity, the Seebeck coefficient and the power factor have been evaluated at two temperatures (300 K and 900 K) and two charge carrier concentrations (1018 cm−3 and 1.2 × 1020 cm−3 electrons and holes). Up to 3% of both compressive and tensile strains have been applied to the material. From our results, we can highlight that a significant improvement of both the Seebeck coefficient (S) and the power factor (PF) is obtained at low temperature and moderate n-doping. The increase in S and PF amounts to 40% and 100%, respectively, compared to the unstrained Mg2Si.