Abstract
Among the large number of promising two-dimensional (2D) atomic layer crystals, true metallic layers are rare. Using combined theoretical and experimental approaches, we report on the stability and successful exfoliation of atomically thin "gallenene" sheets on a silicon substrate, which has two distinct atomic arrangements along crystallographic twin directions of the parent a-gallium. With a weak interface between solid and molten phases of gallium, a solid-melt interface exfoliation technique is developed to extract these layers. Phonon dispersion calculations showthat gallenene can be stabilized with bulk gallium lattice parameters. The electronic band structure of gallenene shows a combination of partially filled Dirac cone and the nonlinear dispersive band near the Fermi level, suggesting that gallenene should behave as a metallic layer. Furthermore, it is observed that the strong interaction of gallenene with other 2D semiconductors induces semiconducting to metallic phase transitions in the latter, paving the way for using gallenene as promising metallic contacts in 2D devices.
| Original language | English |
|---|---|
| Article number | e1701373 |
| Journal | Science advances |
| Volume | 4 |
| Issue number | 3 |
| DOIs | |
| State | Published - 9 Mar 2018 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).
Funding
This research was sponsored by the Air Force Office of Scientific Research under award no. FA9550-14-1-0268. A.S. and A.K.S. acknowledge the Indo-US Science and Technology Forum, Government of India, for providing the Indo-US Research Fellowship. V.K. acknowledges the Rice Center for Quantum Materials/Smalley-Curl Postdoctoral Fellowship in Quantum Materials, and A.S.S. acknowledges the Evans Atwell Postdoctoral Fellowship from the Smalley-Curl Institute at Rice University. Author contributions: A.S. and A.K.S. performed theoretical calculations. V.K., Y.Z., A.S., C.S.T., R.V., and P.M.A. planned and performed the experiments. S.B., P.M., C.S.T., and S.A.S.A. performed mechanical experiments. A.A.S. performed imaging and spectroscopy. All the authors discussed the results and wrote the paper. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.
| Funders | Funder number |
|---|---|
| Air Force Office of Scientific Research | FA9550-14-1-0268 |
| Indo-US Science and Technology Forum |