Effect of uniaxial strains on electronic and optical properties of SnSe from first-principles calculations

In this work, we systematically investigate the uniaxial strain dependence of the electronic and optical properties of SnSe using first-principles calculations and the Bethe-Salpeter equation (BSE) approach. The calculated results show that uniaxial strains significantly affect the main peaks of density of states (DOS) in the valence band and conduction band through the influence on the densities of Sn s/p-states and Se p-state. The main peaks of the real e1(?) and imaginary e2(?) parts of the dielectric function can be enhanced by suitable uniaxial strains. In particular, the peaks of e1(?) and e2(?) along the a-axis increase by 34.8 % and 54.8 % with a red shift under the strain ea = -6 %, respectively. The high absorption coefficient in a wide energy range induced by uniaxial strains suggests a bright prospect for its applications in solar energy conversion. Our work indicates that strain engineering can be an efficient method to modulate the optical properties of SnSe and opens up a new avenue to its practical application.

Automated summary

In this study, the influence of uniaxial strain on the electronic and optical properties of SnSe was investigated using first-principles calculations and the Bethe-Salpeter equation (BSE) approach. The results showed that uniaxial strains have a significant impact on the density of states (DOS) in the valence and conduction bands by affecting the densities of Sn s/p-states and Se p-state. Suitable uniaxial strains can enhance the main peaks of the dielectric function's real (e1(?)) and imaginary (e2(?)) parts. The findings suggest that strain engineering can effectively modulate the optical properties of SnSe and has potential applications in solar energy conversion.