Spatially resolved electronic structure of twisted graphene
| Autor: | Qirong Yao, Paul Leonardus de Boeij, Kai Sotthewes, Shengjun Yuan, Pantelis Bampoulis, Guus J. Slotman, Lijie Zhang, Sebastiaan Haartsen, Henricus J.W. Zandvliet, Arie van Houselt, Rik van Bremen |
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| Přispěvatelé: | Physics of Interfaces and Nanomaterials, Physics of Fluids, Advanced Technology |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Theory of Condensed Matter FOS: Physical sciences 02 engineering and technology Electronic structure 01 natural sciences law.invention symbols.namesake Highly oriented pyrolytic graphite law Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Twist 010306 general physics Condensed Matter - Materials Science Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics Graphene Fermi level Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology Coupling (probability) symbols Density of states 0210 nano-technology Graphene nanoribbons |
| Zdroj: | Physical review B: Covering condensed matter and materials physics, 95(24):245116. American Institute of Physics Physical Review B, 95, pp. 1-6 MESA+ Meeting 2017 Physical Review B, 95, 1-6 |
| ISSN: | 2469-9950 |
| Popis: | We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moire pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (about 1-3.5 degree) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sub-lattices. For energies |E-E_F|>0.3 eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sub-lattices in the moire pattern. Our experimental results are in excellent agreement with the tight-binding calculations. To appear in Phys. Rev. B |
| Databáze: | OpenAIRE |
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