Abstract
Engineering layer-layer interactions provides a powerful way to realize novel and designable quantum phenomena in van der Waals heterostructures. Interlayer electron-electron interactions, for example, have enabled fascinating physics that is difficult to achieve in a single material, such as the Hofstadter's butterfly in graphene/boron nitride (hBN) heterostructures. In addition to electron-electron interactions, interlayer electron-phonon interactions allow for further control of the physical properties of van der Waals heterostructures. Here we report an interlayer electron-phonon interaction in WSe 2 /hBN heterostructures, where optically silent hBN phonons emerge in Raman spectra with strong intensities through resonant coupling to WSe 2 electronic transitions. Excitation spectroscopy reveals the double-resonance nature of such enhancement, and identifies the two resonant states to be the A exciton transition of monolayer WSe 2 and a new hybrid state present only in WSe 2 /hBN heterostructures. The observation of an interlayer electron-phonon interaction could open up new ways to engineer electrons and phonons for device applications.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 127-131 |
| Number of pages | 5 |
| Journal | Nature Physics |
| Volume | 13 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2017 |
Funding
We thank S. Kahn for technical suggestions on heterostructure preparation and J. Yuk for fruitful discussions on sample characterization. This work was primarily supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division of the US Department of Energy under Contract No. DE-AC02-05-CH11231 (van der Waals heterostructures program, KCWF16), and was supported in part by previous breakthroughs obtained through the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under US Department of Energy Contract No. DE-AC02-05CH11231. F.W. also acknowledges support from a David and Lucile Packard fellowship. S.T. acknowledges support from NSF CAREER award DMR 1552220. Growth of hexagonal boron nitride crystals was supported by the Elemental Strategy Initiative conducted by the MEXT, Japan and a Grant-in-Aid for Scientific Research on Innovative Areas ‘Science of Atomic Layers’ from JSPS.
ASJC Scopus subject areas
- General Physics and Astronomy