First-principles study of monolayer and bilayer TaSe$_2$*

Two-dimensional atomic crystals of transition metal dichalcogenides (such as MoS$_2$, TaSe$_2$, etc.) are currently attracting growing attention due to the broad variety of electronic properties presented in these systems. Here we present a first-principles study of the structural, electronic and vibrational properties of monolayer and bilayer TaSe$_2$, which is a charge-density wave material in the bulk form. The structure of monolayer TaSe$_2$ is determined by performing a series of total energy calculations. For bilayer TaSe$_2$, various stackings of monolayer TaSe$_2$ with the hexagonal (2H) and the trigonal (1T) phases, will be considered. Calculated electronic and phonon properties of the energetically favorable states will be compared with the available experimental data.