Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 22: Correlated Electrons: Low-dimensional Systems - Materials 1

TT 22.12: Talk

Wednesday, March 28, 2012, 12:30–12:45, H 0104

Realignment of the charge density wave in TiSe₂ by variation of the conduction band population — •Matthias M. May^1,2, Christoph Janowitz¹, and Recardo Manzke¹ — ¹Humboldt-Universität zu Berlin, Institut für Physik, D-12489 Berlin — ²Helmholtz-Zentrum Berlin, Institut Solare Brennstoffe und Energiespeichermaterialien, D-14109 Berlin

Recent experimental [1] and theoretical [2] studies of the charge density wave phase of TiSe₂ have pronounced the strong excitonic contributions to this phase transition. The effect of increasing the conduction band population by water adsorption [1] was studied with ARPES. Our results suggest a change of the energetically most favourable direction of the electronic superstructure in k-space above a certain population threshold: The 2x2 in plane part of the 2x2x2 superstructure is observable by ARPES for low H₂O-coverage, whereas the perpendicular x2 signature appears only for higher coverage, after the 2x2 has been reduced.

[1] May et al., Phys. Rev. Lett. 107, 176405 (2011)

[2] van Wezel et al., Phys. Rev. B 81, 165109 (2010)