Journal article

Ultrafast electronic band gap control in an excitonic insulator

  • Mor, Selene Fritz-Haber-Institut der MPG, Berlin, Germany
  • Herzog, Marc Fritz-Haber-Institut der MPG, Berlin, Germany - Institute for Physics and Astronomy, University of Potsdam, Germany
  • Golež, Denis Department of Physics, University of Fribourg, Switzerland
  • Werner, Philipp Department of Physics, University of Fribourg, Switzerland
  • Eckstein, Martin Department of Physics, University of Erlangen-Nürnberg, Erlangen, Germany
  • Katayama, Naoyuki Department of Physical Science and Engineering, Nagoya University, Japan
  • Nohara, Minoru Research Institute for Interdisciplinary Science, Okayama University, Japan
  • Takagi, Hide Max Planck Institute for Solid State Research, Stuttgart, Germany - Department of Physics, University of Tokyo, Japan
  • Mizokawa, Takashi Department of Applied Physics, Waseda University, Tokyo, Japan
  • Monney, Claude Institute of Physics, University of Zurich, Switzerland
  • Stähler, Julia Fritz-Haber-Institut der MPG, Berlin, Germany
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    23.08.2017
Published in:
  • Physical Review Letters. - 2017, vol. 119, no. 8, p. 086401
English We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta2NiSe5 investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of FC=0.2 mJ cm−2, the band gap narrows transiently, while it is enhanced above FC. Hartree-Fock calculations reveal that this effect can be explained by the presence of the low- temperature excitonic insulator phase of Ta2NiSe5, whose order parameter is connected to the gap size. This work demonstrates the ability to manipulate the band gap of Ta2NiSe5 with light on the femtosecond time scale.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/306110
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