Temperature-dependent photoemission on 1T-TiSe2: Interpretation within the exciton condensate phase model

Claude Monney (1) , Eike Schwier (1) , Michael Gunnar Garnier (1) , Clement Didiot (1) , Hans Beck (1) , Philipp Aebi (1) , Hervé Cercellier (2) , Jacques Marcus (3) , Corsin Battaglia (4) , Helmut Berger (4) , A.N. Titov (5)

1 UNIFR - Université de Fribourg = University of Fribourg
2 NEEL - MagSup - Magnétisme et Supraconductivité
3 NEEL - AUTOCARAC - Automatisation & caractérisation
4 EPFL - Ecole Polytechnique Fédérale de Lausanne
5 Inst Met Phys, UrD

The charge-density-wave phase transition of 1T-TiSe2 is studied by angle-resolved photoemission over a wide temperature range. An important chemical-potential shift which strongly evolves with temperature is evidenced. In the framework of the exciton condensate phase, the detailed temperature dependence of the associated order parameter is extracted. Having a mean-field-like behavior at low temperature, it exhibits a nonzero value above the transition, interpreted as the signature of strong excitonic fluctuations, reminiscent of the pseudogap phase of high-temperature superconductors. Integrated intensity around the Fermi level is found to display a trend similar to the measured resistivity and is discussed within the model.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Claude Monney, Eike Schwier, Michael Gunnar Garnier, Clement Didiot, Hans Beck, et al.. Temperature-dependent photoemission on 1T-TiSe2: Interpretation within the exciton condensate phase model. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 81 (15), pp.155104. ⟨10.1103/PhysRevB.81.155104⟩. ⟨hal-00966146⟩