Twist-tailoring Coulomb correlations in van der Waals homobilayers
Journal article, 2020
The recent discovery of artificial phase transitions induced by stacking monolayer materials at magic twist angles represents a paradigm shift for solid state physics. Twist-induced changes of the single-particle band structure have been studied extensively, yet a precise understanding of the underlying Coulomb correlations has remained challenging. Here we reveal in experiment and theory, how the twist angle alone affects the Coulomb-induced internal structure and mutual interactions of excitons. In homobilayers of WSe2, we trace the internal 1s–2p resonance of excitons with phase-locked mid-infrared pulses as a function of the twist angle. Remarkably, the exciton binding energy is renormalized by up to a factor of two, their lifetime exhibits an enhancement by more than an order of magnitude, and the exciton-exciton interaction is widely tunable. Our work opens the possibility of tailoring quasiparticles in search of unexplored phases of matter in a broad range of van der Waals heterostructures.
Author
Philipp Merkl
University of Regensburg
F. Mooshammer
University of Regensburg
Samuel Brem
Chalmers, Physics, Condensed Matter and Materials Theory
Anna Girnghuber
University of Regensburg
Kai Qiang Lin
University of Regensburg
Leonard Weigl
University of Regensburg
Marlene Liebich
University of Regensburg
Chaw Keong Yong
University of Regensburg
Roland Gillen
University of Erlangen-Nuremberg (FAU)
Janina Maultzsch
University of Erlangen-Nuremberg (FAU)
J. M. Lupton
University of Regensburg
Ermin Malic
2D-Tech
Chalmers, Physics, Condensed Matter and Materials Theory
R. Huber
University of Regensburg
Nature Communications
2041-1723 (ISSN) 20411723 (eISSN)
Vol. 11 1 2167Exciton dynamics in atomically thin materials
Swedish Research Council (VR) (2018-00734), 2019-01-01 -- 2024-12-31.
Graphene Core Project 3 (Graphene Flagship)
European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Subject Categories
Physical Chemistry
Atom and Molecular Physics and Optics
Condensed Matter Physics
DOI
10.1038/s41467-020-16069-z