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Søren Ulstrup

Layer and orbital interference effects in photoemission from transition metal dichalcogenides

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  • Habib Rostami, Stockholm Univ, Stockholm University, Stockholm Resilience Ctr
  • ,
  • Klara Volckaert
  • Nicola Lanata
  • Sanjoy K. Mahatha
  • ,
  • Charlotte E. Sanders, STFC Rutherford Appleton Lab, STFC Rutherford Appleton Laboratory, Science & Technology Facilities Council (STFC), Cent Laser Facil
  • ,
  • Marco Bianchi
  • Daniel Lizzit, Elettra-Sincrotrone Trieste, Trieste,
  • Luca Bignardi, Univ Trieste, University of Trieste, Dept Phys
  • ,
  • Silvano Lizzit, Elettra-Sincrotrone Trieste, Trieste,
  • Jill A. Miwa
  • Alexander Balatsky, Stockholm Univ, Stockholm University, Stockholm Resilience Ctr
  • ,
  • Philip Hofmann
  • Søren Ulstrup

In this work, we provide an effective model to evaluate the one-electron dipole matrix elements governing optical excitations and the photoemission process of single-layer (SL) and bilayer (BL) transition metal dichalcogenides. By utilizing a k . p Hamiltonian, we calculate the photoemission intensity as observed in angle-resolved photoemission from the valence bands around the (K) over bar valley of MoS2. In SL MoS2, we find a significant masking of intensity outside the first Brillouin zone, which originates from an in-plane interference effect between photoelectrons emitted from the Mo d orbitals. In BL MoS2, an additional interlayer interference effect leads to a distinctive modulation of intensity with photon energy. Finally, we use the semiconductor Bloch equations to model the optical excitation in a time- and angle-resolved pump-probe photoemission experiment. We find that the momentum dependence of an optically excited population in the conduction band leads to an observable dichroism in both SL and BL MoS2.

Original languageEnglish
Article number235423
JournalPhysical Review B
Number of pages9
Publication statusPublished - 2019

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