Structural, electronic, and optical properties of two-dimensional hafnium monoxide nanosheets

Ultrathin two-dimensional transition metal oxides are highly desirable as promising materials for energy storage, gas sensors, photonic and electronic devices. In this work, we studied the structural stability, electronic structure and optical properties of two-dimensional hafnium monoxide with hexagonal and tetragonal lattice by the first principles calculations. Phonon dispersion reveals the lattice dynamic stability of hexagonal structures. Results of band structure showed that both hexagonal and tetragonal HfO nanosheets had highly anisotropic metallic behavior. The optical properties showed strong light absorption and anisotropy.