Strain‐tunable electronic properties and optical properties of <scp>Hf<sub>2</sub>CO<sub>2</sub> MXene</scp>
Shanshan Li, Xiao‐Hong Li, Rui‐Zhou Zhang, Hong‐Ling Cui
Abstract
Abstract Two‐dimensional materials have been extensively applied because of their unusual electronic, mechanical, and optical properties. In this paper, the electronic structure and optical properties of Hf 2 CO 2 MXene under biaxial and uniaxial strains are investigated by the Heys‐Scuseria‐Ernzerhof (HSE06) method. Monolayer Hf 2 CO 2 can sustain stress up to 6.453 N/M for biaxial strain and 3.072 N/M for uniaxial strain. Monolayer Hf 2 CO 2 undergoes the transition from semiconductor to metal under −12% strain whether it is under biaxial or uniaxial strain. With the increasing biaxial compressive strain, the blue shift of Hf‐d, O‐p, and C‐p orbitals in valence band maximum results in the metallization of monolayer Hf 2 CO 2 , while the red shift of Hf‐d and O‐p orbitals in conduction band minimum results in the metallization of monolayer Hf 2 CO 2 with increasing uniaxial compressive strain. The analysis of optical properties indicates that uniaxial strain weakens the reflectivity and refractive index of monolayer Hf 2 CO 2 in the visible‐light range. In addition, the effective mass and the charge distribution under biaxial and uniaxial strains are also explored.