Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 80: Surface Dynamics I

O 80.5: Vortrag

Donnerstag, 3. April 2014, 17:00–17:15, GER 38

Time-resolved photoemission spectroscopy on 1T–TaSe₂: Mott physics at the surface? — •Christian Sohrt, Ankatrin Stange, Lutz Kipp, Michael Bauer, and Kai Rossnagel — Institute for Experimental and Applied Physics, University of Kiel, Germany

According to angle-resolved photoelectron spectroscopy and scanning tunneling microscopy studies, the surface of 1T–TaSe₂ displays Mott insulating behavior in connection with a commensurate √13×√13 charge-density wave, in a similar way as observed in 1T–TaS₂ [1,2]. But the question is whether the observed spectral gap at the Fermi level is really a Mott gap.
A possible smoking-gun experiment to answer this question is time- and angle-resolved photoelectron spectroscopy (trARPES), which in principle enables us to distinguish between Peierls and Mott gaps by direct determination of the gap quenching times [3].
Here, we present the results of a comparative momentum-dependent trARPES study on 1T–TaSe₂ and 1T–TaS₂. In contrast to the prevailing view, no indications for Mott dynamics are found at the surface of 1T–TaSe₂.
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