26 July 2023

Exciton Ensembles Manifest Coherence

An international team lead by Alexander Holleitner, Prof. at TUM and MCQST member, achieved a significant breakthrough in condensed-matter physics, which has been featured in an synopsis article in Physics Magazine.

The researchers investigated excitons, particle-like entities formed when electrons bind to holes in a condensed-matter system. The team of researchers aimed to achieve a collective quantum state of excitons, known as a Bose-Einstein condensate, in a two-dimensional (2D) material. They successfully observed that an ensemble of excitons in a 2D-material system emitted light coherently. The study utilized a stacked structure of two 2D semiconducting materials, MoSe2 and WSe2, and employed point-inversion Michelson-Morley interferometry to analyze the emitted light. The coherence length and temporal coherence time of excitons were investigated at different temperatures, with lower temperatures being crucial for further studying the creation of a Bose-Einstein condensate of excitons.
The exciting breakthrough could provide valuable insights into quantum effects and open up possibilities for quantum technology applications.

Publication

Extended Spatial Coherence of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
M.Troue, J. Figueiredo, L. Sigl, C. Paspalides, M., T. Taniguchi, K. Watanabe, M. Selig, A. Knorr, U. Wurstbauer, and A. W. Holleitner.
Phys. Rev. Lett. 131, 036902 (2023)
DOI: 10.1103/PhysRevLett.131.036902