Twist-tailoring Coulomb correlations in van der Waals homobilayers
Artikel i vetenskaplig tidskrift, 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.


Philipp Merkl

Universität Regensburg

F. Mooshammer

Universität Regensburg

Samuel Brem

Chalmers, Fysik, Kondenserad materie- och materialteori

Anna Girnghuber

Universität Regensburg

Kai Qiang Lin

Universität Regensburg

Leonard Weigl

Universität Regensburg

Marlene Liebich

Universität Regensburg

Chaw Keong Yong

Universität Regensburg

Roland Gillen

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

Janina Maultzsch

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

J. M. Lupton

Universität Regensburg

Ermin Malic


Chalmers, Fysik, Kondenserad materie- och materialteori

R. Huber

Universität Regensburg

Nature Communications

2041-1723 (ISSN)

Vol. 11 1 2167

Excitondynamik i atomiskt tunna material

Vetenskapsrådet (VR) (2018-00734), 2019-01-01 -- 2024-12-31.

Graphene Core Project 3 (Graphene Flagship)

Europeiska kommissionen (EU) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.


Fysikalisk kemi

Atom- och molekylfysik och optik

Den kondenserade materiens fysik



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