Faculté des sciences

Pseudogapped Fermi surfaces of 1T-TaS2 and 1T-TaSe2: A charge density wave effect

Bovet, M. ; Popovic, D. ; Clerc, F. ; Koitzsch, Christian ; Probst, U. ; Bucher, E. ; Berger, H. ; Naumovic, D. ; Aebi, Philipp

In: Physical Review B, 2004, vol. 69, no. 125117, p. 1-9

We report room temperature angle-resolved photoemission experiments on 1T-TaS2 and 1T-TaSe2 complemented by density-functional theory calculations. Fermi-surface mapping experiments in the charge-density wave (CDW) phase are similar for the two compounds and do not show symmetries due to the CDW-induced new Brillouin zones. However, the band structure a few eV... Plus

Ajouter à la liste personnelle
    Summary
    We report room temperature angle-resolved photoemission experiments on 1T-TaS2 and 1T-TaSe2 complemented by density-functional theory calculations. Fermi-surface mapping experiments in the charge-density wave (CDW) phase are similar for the two compounds and do not show symmetries due to the CDW-induced new Brillouin zones. However, the band structure a few eV below the Fermi level (EF) displays a clear modulation that we relate, in both cases, to the CDW. At EF, the spectral weight distribution reflects the band structure of the normal state, but no clear quasiparticle crossing is located. Near the zone center Γ̅ , CDW-split quasilocalized Ta dz2 subbands are observed in the vicinity of EF. For 1T-TaS2 and 1T-TaSe2, they are thermally populated slightly above EF and close to EF, respectively. The observed behavior can be understood in terms of the CDW reconstructed, spectral function weighted band structure.