Strain sensitivity of band structure and electron mobility in perovskite BaSnO₃: first-principles calculation

A first-principles electronic structure calculation is utilized to contrastively investigate the crystal structure, band structure, electron effective mass and mobility of perovskite BaSnO₃ under hydrostatic and biaxial strain. Strain-induced changes in relative properties are remarkable and more sensitive to hydrostatic strain than biaxial strain. The structure of BaSnO₃ remains cubic under hydrostatic strain, while it becomes tetragonal under biaxial strain. Originating from the strain sensitivity of the Sn 5s orbitals in the conduction band minimum, the band gaps of BaSnO₃ decrease for both types of strain from -3% to 3%. BaSnO₃ under tensile hydrostatic strain exhibits higher electron mobility than it does under tensile biaxial strain because of the smaller electron effective mass in the corresponding strain. In contrast, the opposite phenomenon exists in compressive strain. Our results demonstrate that strain could be an alternative way to modify the band gap and electron mobility of BaSnO₃.