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Sahar Pakdel

Quenching of Exciton Recombination in Strained Two-Dimensional Monochalcogenides

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  • J. J. Esteve-Paredes, Univ Autonoma Madrid, Autonomous University of Madrid, Dept Fis Mat Condensada
  • ,
  • Sahar Pakde
  • J. J. Palacios, Univ Texas Austin, University of Texas System, University of Texas Austin, Dept Phys, Universidad Autónoma de Madrid

We predict that long-lived excitons with very large binding energies can also exist in a single or few layers of monochalcogenides such as GaSe. Our theoretical study shows that excitons confined by a radial local strain field are unable to recombine despite electrons and holes coexisting in space. The localized single-particle states are calculated in the envelope function approximation based on a three-band k . p Hamiltonian obtained from density-functional-theory calculations. The binding energy and the decay rate of the exciton ground state are computed after including correlations in the basis of electron-hole pairs. The interplay between the localized strain and the caldera-type valence band characteristic of few-layered monochalcogenides creates localized electron and hole states with very different quantum numbers which hinders the recombination even for singlet excitons.

TidsskriftPhysical Review Letters
Antal sider6
StatusUdgivet - aug. 2019

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