Spectroscopic Observation Of Charge-Density-Wave-Induced Changes In The Electronic-Structure Of 2H-Tase2

We have performed a high-energy-resolution photoelectron spectroscopy investigation of the quasi-two-dimensional material 2H-TaSe2. Temperature-dependent constant-binding energy curves reveal that characteristic changes in the electronic density of states occur continuously through the second-order charge-density-wave (CDW) transition at 122 K. The photoelectron spectra indicate that different parts of the Fermi surface are unequally affected by the CDW and suggest the formation of an energy gap in the GAMMAK direction of the Brillouin zone.