• DOI:10.1126/sciadv.abg0192
• Corpus ID: 227208818

Experimental measurement of the intrinsic excitonic wave function

@article{Man2020ExperimentalMO,
  title={Experimental measurement of the intrinsic excitonic wave function},
  author={Michael K. L. Man and Julien Mad{\'e}o and Chakradhar Sahoo and Kaichen Xie and Marshall Campbell and Vivek Pareek and Arka Karmakar and E. Laine Wong and Abdullah Al‐Mahboob and Nicholas S. Chan and David R. Bacon and Xing Zhu and Mohamed Abdelrasoul and Xiaoqin Li and Tony F. Heinz and Felipe H. da Jornada and Ting Cao and Keshav M. Dani},
  journal={Science Advances},
  year={2020},
  volume={7}
}

• M. Man, J. Madéo, +15 authors K. Dani
• Published 26 November 2020
• Physics
• Science Advances

We visualize the distribution of the electron around the hole in an exciton and observe its elusive anomalous dispersion. An exciton, a two-body composite quasiparticle formed of an electron and hole, is a fundamental optical excitation in condensed matter systems. Since its discovery nearly a century ago, a measurement of the excitonic wave function has remained beyond experimental reach. Here, we directly image the excitonic wave function in reciprocal space by measuring the momentum distribution of electrons photoemitted from excitons in monolayer tungsten diselenide. By transforming to real space, we obtain a visual of the distribution of the electron around the hole in an exciton. Further, by also resolving the energy coordinate, we confirm the elusive theoretical prediction that the photoemitted electron exhibits an inverted energy-momentum dispersion relationship reflecting the valence band where the partner hole remains, rather than that of conduction band states of the electron.