Anisotropic electronic and plasmonic properties of 2H-TiS₂

Plasmon characteristics in a monolayer of 2H-TiS₂ in the presence of strain are carefully analyzed by employing the density functional theory along with random phase approximation. The anisotropic properties of 2H-TiS₂ are carefully analyzed under biaxial strains. An anisotropic semi-Dirac cone in the electronic band-structure is observed at a specific biaxial strain configuration. This unique characteristic can be explained by the hybridization of orbitals at the conduction band minimum and valence band maximum which can be effectively tuned by applying strain. The effect of anisotropic electronic band-structure on the properties of plasmons is investigated by utilizing the electron energy loss spectrum analysis. A $\sqrt{q}$ dispersion along the Γ−K direction and a linear dispersion along the $\Gamma -M^{{}^{\prime }}$ were found. The linear dispersion characterizes an extrinsic acoustic plasmon mode that can be tuned by the carrier concentration. (paper)