Tuning electronic properties of pentagonal PdSe2 monolayer by applying external strain

We investigate the tuning of the electronic properties of pentagonal PdSe2 monolayer by applying external strain. We find that the electronic structure of PdSe2 monolayer can be flexibly modulated by applying the uniaxial as well as biaxial strains. Under the tensile strain (uniaxial or biaxial), the bandgap remains indirect with CBM at M point and VBM at a k-point along the Γ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varGamma $$\end{document}-X path. The bandgap decreases monotonically from 1.34 to 0.83 eV (0.34 eV) under uniaxial (biaxial) tensile strains of 8%. Under compressive strain, the bandgap transforms from indirect to quasi-direct with both CBM and VBM at k-points along the Γ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varGamma $$\end{document}-X path. The change in bandgap under compressive strain is not significant as compared to corresponding value of tensile strains.