Direct measurement of key exciton properties: energy, dynamics and spatial distribution of the wave function
Abstract
Excitons, Coulomb-bound electron-hole pairs, are the fundamental excitations governing the optoelectronic properties of semiconductors. While optical signatures of excitons have been studied extensively, experimental access to the excitonic wave function itself has been elusive. Using multidimensional photoemission spectroscopy, we present a momentum-, energy- and time-resolved perspective on excitons in the layered semiconductor WSe. By tuning the excitation wavelength, we determine the energy-momentum signature of bright exciton formation and its difference from conventional single-particle excited states. The multidimensional data allows to retrieve fundamental exciton properties like the binding energy and the exciton-lattice coupling and to reconstruct the real-space excitonic distribution function via Fourier transform. All quantities are in excellent agreement with microscopic calculations. Our approach provides a full characterization of the exciton properties and is applicable to bright and dark excitons in semiconducting materials, heterostructures and devices.
Keywords
Cite
@article{arxiv.2012.15328,
title = {Direct measurement of key exciton properties: energy, dynamics and spatial distribution of the wave function},
author = {Shuo Dong and Michele Puppin and Tommaso Pincelli and Samuel Beaulieu and Dominik Christiansen and Hannes Hubener and Christopher W. Nicholson and R. Patrick Xian and Maciej Dendzik and Yunpei Deng and Yoav William Windsor and Malte Selig and Ermin Malic and Angel Rubio and Andreas Knorr and Martin Wolf and Laurenz Rettig and Ralph Ernstorfer},
journal= {arXiv preprint arXiv:2012.15328},
year = {2021}
}