We have performed the band structure calculations for the normal phase of 2H-MX2(M=Nb,Ta,X=S,Se) and the 3×3 commensurate CDW (C-CDW) phase of 2H-TaSe2. In 2H-TaSe2 the density of states shows a peak structure near the Fermi level in the normal phase, then becomes largely reduced after formation of the CDW. It allows us to discuss the new mechanism for the CDW instability.
- Charge density wave
- Electronic band structure
- Transition metal di-chalcogeneides