Reversal of charge transfer doping on the negative electronic compressibility surface of MoS2

The strong electron-electron interaction in transition metal dichalcogenides (TMDs) gives rise to phenomena such as strong exciton and trion binding and excitonic condensation, as well as large negative exchange and correlation contributions to the electron energies, resulting in negative electronic...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2024-09
Main Authors: Watson, Liam, Iolanda Di Bernardo, Blyth, James, Lowe, Benjamin, Thi-Hai-Yen Vu, McEwen, Daniel, Edmonds, Mark T, Tadich, Anton, Fuhrer, Michael S
Format: Article
Language:English
Subjects:
Binding energy
Carrier density
Chalcogenides
Charge reversal
Charge transfer
Compressibility effects
Current carriers
Doping
Electrons
Excitons
Low dimensional semiconductors
Many body problem
Molybdenum disulfide
Photoelectric emission
Subtraction
Surface layers
Transition metal compounds
Two dimensional bodies
Valence band
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The strong electron-electron interaction in transition metal dichalcogenides (TMDs) gives rise to phenomena such as strong exciton and trion binding and excitonic condensation, as well as large negative exchange and correlation contributions to the electron energies, resulting in negative electronic compressibility. Here we use angle-resolved photoemission spectroscopy to demonstrate a striking effect of negative electronic compressibility in semiconducting TMD MoS2 on the charge transfer to and from a partial overlayer of monolayer semimetallic WTe2. We track the changes in binding energy of the valence bands of both WTe2 and MoS2 as a function of surface transfer doping with donor (K) and acceptor (F4-TCNQ) species. Donor doping increases the binding energy of the MoS2 valence band, as expected, while counterintuitively reducing the binding energy of the WTe2 valence bands and core levels. The inverse effect is observed for acceptor doping, where a typical reduction in the MoS2 binding energies is accopanied by an unexpected increase in those of WTe2. The observations imply a reversal of the expected charge transfer; donor (acceptor) deposition decreases (increases) the carrier density in the WTe2 adlayer. The charge transfer reversal is a direct consequence of the negative electronic compressibility of the MoS2 surface layer, for which addition (subtraction) of charge leads to attraction (repulsion) of further charge from neighbouring layers. These findings highlight the importance of many-body interactions for the electrons in transition metal dichalcogenides and underscore the potential for exploring strongly correlated quantum states in two-dimensional semiconductors.
ISSN:2331-8422