Electronic structure of 1T-TiS2

We present state-of-the-art band-structure calculations for the 1T phase of TiS2. We have used the full-potential linear augmented-plane-wave method a s embodied in the WIEN97 code. Our calculations show that 1T-TiS2 is semime tallic at ambient pressure in agreement with the recent calculations based on the augmented spherical wave (ASW) and the linear-muffin-tin-orbital met hods but in disagreement with the more recent pseudopotential calculations. In order to ascertain the effect of lattice parameters on the band structu re, we have performed calculations for lattice parameters corresponding to hydrostatic pressures up to 7.6 GPa. Our calculations show that 1T-TiS2 rem ains semimetallic at these pressures. Calculations are also performed for t he slab geometry to ascertain whether the band overlap decreases with incre asing distance between the TiS2 layers making it a semiconductor as reveale d by the ASW calculations. We find that 1T-TiS2 is semimetallic in the slab geometry, too.