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Pseudogapped Fermi surfaces of 1<i>T</i>-TaS<sub>2</sub> and 1<i>T</i>-TaSe<sub>2</sub>: A charge density wave effect
Auteur(s)
Bovet, M.
Popovic, D.
Clerc, F.
Koitzsch, Christian
Probst, U.
Bucher, E.
Berger, H.
Naumovic, D.
Aebi, Philipp
Date de parution
2004
In
Physical Review B, American Physical Society (APS), 2004/69/125117/1-9
Résumé
We report room temperature angle-resolved photoemission experiments on 1<i>T</i>-TaS<sub>2</sub> and 1<i>T</i>-TaSe<sub>2</sub> 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 (<i>E<sub>F</sub></i>) displays a clear modulation that we relate, in both cases, to the CDW. At <i>E<sub>F</sub></i>, 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 <i>dz<sup>2</sup></i> subbands are observed in the vicinity of <i>E<sub>F</sub></i>. For 1<i>T</i>-TaS<sub>2</sub> and 1<i>T</i>-TaSe<sub>2</sub>, they are thermally populated slightly above <i>E<sub>F</sub></i> and close to <i>E<sub>F</sub></i>, respectively. The observed behavior can be understood in terms of the CDW reconstructed, spectral function weighted band structure.
Identifiants
Type de publication
journal article
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