Temperature-dependent Fermi surface of 2H-TaSe2 driven by competing density wave order fluctuations
Temperature evolution of the 2H-TaSe2 Fermi surface (FS) is studied by high-resolution angle-resolved photoemission spectroscopy. High-accuracy determination of the FS geometry was possible after measuring electron momenta and velocities along all high-symmetry directions as a function of temperature with subsequent fitting to a tight-binding model. The estimated incommensurability parameter of the nesting vector agrees with that of the incommensurate charge modulations. We observe detectable nonmonotonic temperature dependence of the FS shape, which we show to be consistent with the analogous behavior of the pseudogap. These changes in the electronic structure could stem from the competition of commensurate and incommensurate charge density wave order fluctuations and could explain the puzzling reopening of the pseudogap observed in the normal state of the transition metal dichalcogenides.
Keywords: charge density waves ; commensurate-incommensurate transformations ; electronic structure ; Fermi surface ; photoelectron spectra ; tantalum compounds ; tight-binding calculations ; Resolution Photoemission-Spectroscopy ; Charge-Density ; Quasi-Crystals ; Electronic-Structure ; Neutron-Scattering ; Peierls Transition ; Superconductors ; Energy ; Pseudogap ; Insulator
Record created on 2010-11-30, modified on 2016-08-09