Journal article

Photoenhanced excitonic correlations in a Mott insulator with nonlocal interactions

  • Bittner, Nikolaj Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
  • Golež, Denis Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland - Flatiron Institute, Simons Foundation, 162 Fifth Avenue, New York, New York 10010, USA
  • Eckstein, Martin Department of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
  • Werner, Philipp Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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    18.02.2020
Published in:
  • Physical Review B. - 2020, vol. 101, no. 8, p. 085127
English We investigate the effect of nonlocal interactions on the photodoped Mott insulating state of the two-dimensional Hubbard model using a nonequilibrium generalization of the dynamical cluster approximation. In particular, we compare the situation where the excitonic states are lying within the continuum of doublon-holon excitations to a setup where the excitons appear within the Mott gap. In the first case, the creation of nearest-neighbor doublon-holon pairs by excitations across the Mott gap results in enhanced excitonic correlations, but these excitons quickly decay into uncorrelated doublons and holons. In the second case, photoexcitation results in long-lived excitonic states. While in a low-temperature equilibrium state, excitonic features are usually not evident in single-particle observables such as the photoemission spectrum, we show that the photoexcited nonequilibrium system can exhibit in-gap states associated with the excitons. The comparison with exact-diagonalization results for small clusters allows us to identify the signatures of the excitons in the photoemission spectrum.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/308637
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