Electronic structure of $1T-{\mathrm{TiS}}_2$

We present state-of-the-art band-structure calculations for the $1T$ phase of ${\mathrm{TiS}}_2.$ We have used the full-potential linear augmented-plane-wave method as embodied in the WIEN97 code. Our calculations show that $1T-{\mathrm{TiS}}_2$ is semimetallic at ambient pressure in agreement with the recent calculations based on the augmented spherical wave (ASW) and the linear-muffin-tin-orbital methods but in disagreement with the more recent pseudopotential calculations. In order to ascertain the effect of lattice parameters on the band structure, we have performed calculations for lattice parameters corresponding to hydrostatic pressures up to 7.6 GPa. Our calculations show that $1T-{\mathrm{TiS}}_2$ remains semimetallic at these pressures. Calculations are also performed for the slab geometry to ascertain whether the band overlap decreases with increasing distance between the ${\mathrm{TiS}}_2$ layers making it a semiconductor as revealed by the ASW calculations. We find that $1T-{\mathrm{TiS}}_2$ is semimetallic in the slab geometry, too.