The effect of uniaxial compressive and tensile strains on the structural, dynamical, electronic, and optical properties of ZrCl2 monolayer: Ab-initio calculations

Abstract

Recently, the two-dimensional material zirconium dihalide (ZrCl₂) has received a significant attention for prospective device applications due to its unique electronic, mechanical, magnetic, and topological properties. This work reports theoretical predictions for the structural, dynamical, electronic, and optical properties of ZrCl₂ under uniaxial compressive and tensile strains using density functional theory (DFT). The band gap structures were found to be highly sensitive to the uniaxial compressive and tensile strains of ZrCl₂ monolayer (ML). The unstrained ZrCl₂ ML has a semiconducting behavior with an indirect band gap of 1.19 eV. Under the uniaxial compressive tensile stress (ε_x) of $-$6%, $-$4%, $-$2%, the ZrCl₂ ML retains the semiconducting behavior with indirect band gaps of 0.00, 0.30, 0.73, respectively. However, the ZrCl₂ ML has a semiconductor behavior with direct band gaps of 0.91, 0.56, and 0.41 eV for applied tensile strains of 2%, 4%, and 6%, respectively. In addition, the optical properties of ZrCl₂ ML are calculated, and the optical absorption is found to exhibit a significant anisotropy in the photon energy range of 0 - 13 eV. Based on the result of the optical properties, a ZrCl₂ ML is expected to potentially be a candidate for optoelectronic applications, such as an infrared photodetector.