Direct Observation of Incommensurate-Commensurate Transition in Graphene-hBN Heterostructures via Optical Second Harmonic Generation
| Autor: | Stepanov, E. A., Semin, S. V., Woods, C. R., Vandelli, M., Kimel, A. V., Novoselov, K. S., Katsnelson, M. I. |
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| Rok vydání: | 2020 |
| Předmět: |
GRAPHENE
ELECTRONIC PROPERTIES Phase transition Materials science OPTICAL SECOND HARMONIC GENERATION Theory of Condensed Matter III-V SEMICONDUCTORS EXPERIMENTAL TECHNIQUES Point reflection HEXAGONAL BORON NITRIDE 02 engineering and technology DIRECT OBSERVATIONS METAL INSULATOR TRANSITION 01 natural sciences law.invention law COMMENSURABILITY SUPERCONDUCTING STATE Spectroscopy of Solids and Interfaces 0103 physical sciences HETEROSTRUCTURES HARMONIC ANALYSIS General Materials Science 010306 general physics THERMAL-ANNEALING NONLINEAR OPTICAL SIGNALS Superconductivity HFML - High Field Magnet Laboratory NONLINEAR OPTICS Condensed matter physics Graphene METAL INSULATOR BOUNDARIES Second-harmonic generation Nonlinear optics Heterojunction INVERSION SYMMETRY 021001 nanoscience & nanotechnology ALIGNMENT HARMONIC GENERATION INCOMMENSURATE PHASE 0210 nano-technology Bilayer graphene SEMICONDUCTOR INSULATOR BOUNDARIES |
| Zdroj: | Acs Applied Materials & Interfaces., 12, 27758-27764 Acs Applied Materials & Interfaces., 12, 24, pp. 27758-27764 ACS Applied Materials and Interfaces ACS Appl. Mater. Interfaces |
| ISSN: | 1944-8244 |
| Popis: | Commensurability effects play a crucial role in the formation of electronic properties of novel layered heterostructures. The interest in these moiré superstructures has increased tremendously since the recent observation of a superconducting state (Nature 2018, 556, 43-50) and metal-insulator transition (Nature 2018, 556, 80-84) in twisted bilayer graphene. In this regard, a straightforward and efficient experimental technique for detection of the alignment of layered materials is desired. In this work, we use optical second harmonic generation, which is sensitive to the inversion symmetry breaking, to investigate the alignment of graphene/hexagonal boron nitride heterostructures. To achieve that, we activate a commensurate-incommensurate phase transition by a thermal annealing of the sample. We find that this structural change in the system can be directly observed via a strong modification of a nonlinear optical signal. Unambiguous interpretation of obtained results reveals the potential of a second harmonic generation technique for probing of structural changes in layered systems. Copyright © 2020 American Chemical Society. The authors thank Chris Berkhout for technical support in nonlinear measurements. The authors also thank Clement Dutreix and Vladimir Kukushkin for fruitful discussions and useful comments. The work of E.A.S. was supported by the Russian Science Foundation, Grant 17-72-20041. K.S.N. acknowledges support from EU Graphene Flagship Program (Contract CNECTICT-604391), European Research Council Synergy Grant Hetero2D, the Royal Society, EPSRC Grant EP/N010345/1. The work of M.I.K. was supported by European Research Council via Synergy Grant 854843 - FASTCORR. |
| Databáze: | OpenAIRE |
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