Abstract
Exotic properties emerge from the electronic structure of few-layer transition-metal dichalcogenides (TMDs), such as direct band gaps in monolayers and moiré excitons in twisted bilayers, which are exploited in modern optoelectronic devices and twistronics. Here, Compton scattering in a transmission electron microscope (TEM) is used to probe the nature of the interlayer electronic coupling in the TMD material WS2. The high spatial resolution and strong scattering in the TEM enables a complete analysis of individual WS2 domains, including their crystal structure. Compton measurements show that the electrons in an 18∘ twisted bilayer are more localized than in a monolayer. Density functional theory simulations reveal this is caused by a twist-induced charge buildup in the interlayer region, directly shielding the energetically unfavorable overlapping tungsten atoms. This unexpected result uncovers the precise role of twist angle on interlayer coupling, and therefore the physical properties that depend on it.
| Original language | English |
|---|---|
| Article number | 235424 |
| Journal | Physical Review B |
| Volume | 107 |
| Issue number | 23 |
| DOIs | |
| State | Published - 15 Jun 2023 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Funding
A.T. acknowledges the UK Engineering and Physical Sciences Research Council (EPSRC) for Ph.D. funding (Grant No. EP/R513039/1) and the Japan Society for the Promotion of Science (JSPS) for support of a pre/postdoctoral research fellowship (Grant No. PE21763) in Japan. A.C., P.K.M., and A.I. gratefully acknowledge the very generous support of the Israel Science Foundation, Project No. 2596/21. Y.X. and T.M. acknowledge the Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) for funding (Grants No. 19H00818 and No. 19H05787). S.J.C. is grateful to Durham University for use of its supercomputing facilities (Hamilton), and also EPSRC under Grant No. EP/X035891/1 for the UK national supercomputing facility Archer 2.
| Funders | Funder number |
|---|---|
| Engineering and Physical Sciences Research Council | EP/R513039/1 |
| Durham University | EP/X035891/1 |
| Japan Society for the Promotion of Science | PE21763 |
| Ministry of Education, Culture, Sports, Science and Technology | 19H05787, 19H00818 |
| Israel Science Foundation | 2596/21 |