Evidence for Strain-Induced Local Conductance Modulations in Single-Layer Graphene on SiO2
| Autor: | Teague, M. L., Lai, A. P., Velasco, J., Hughes, C. R., Beyer, A. D., Bockrath, M. W., Lau, C. N., Yeh, N. -C. |
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| Rok vydání: | 2009 |
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| Zdroj: | Nano Letters Vol. 9, No. 7, 2542 - 2546 (2009) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1021/nl9005657 |
| Popis: | Graphene has emerged as an electronic material that is promising for device applications and for studying two-dimensional electron gases with relativistic dispersion near two Dirac points. Nonetheless, deviations from Dirac-like spectroscopy have been widely reported with varying interpretations. Here we show evidence for strain-induced spatial modulations in the local conductance of single-layer graphene on SiO2 substrates from scanning tunneling microscopic (STM) studies. We find that strained graphene exhibits parabolic, U-shaped conductance vs. bias voltage spectra rather than the V-shaped spectra expected for Dirac fermions, whereas V-shaped spectra are recovered in regions of relaxed graphene. Strain maps derived from the STM studies further reveal direct correlation with the local tunneling conductance. These results are attributed to a strain-induced frequency increase in the out-of-plane phonon mode that mediates the low-energy inelastic charge tunneling into graphene. Comment: 5 pages, 4 figures. Corresponding author: Nai-Chang Yeh (ncyeh@caltech.edu) |
| Databáze: | arXiv |
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