Scanning tunnelling spectroscopic studies of dirac fermions in graphene and topological insulators

N. C. Yeh, M. L. Teague, R. T.P. Wu, H. Chu, D. A. Boyd, M. W. Bockrath, L. He, F. X. Xiu, K. L. Wang

研究成果: Conference article同行評審

5 引文 斯高帕斯(Scopus)

摘要

We report novel properties derived from scanning tunnelling spectroscopic (STS) studies of Dirac fermions in graphene and the surface state (SS) of a strong topological insulator (STI), Bi2Se3. For mono-layer graphene grown on Cu by chemical vapour deposition (CVD), strain-induced scalar and gauge potentials are manifested by the charging effects and the tunnelling conductance peaks at quantized energies, respectively. Additionally, spontaneous time-reversal symmetry breaking is evidenced by the alternating anti-localization and localization spectra associated with the zero-mode of two sublattices while global time-reversal symmetry is preserved under the presence of pseudo-magnetic fields. For Bi2Se3 epitaxial films grown on Si(111) by molecular beam epitaxy (MBE), spatially localized unitary impurity resonances with sensitive dependence on the energy difference between the Fermi level and the Dirac point are observed for samples thicker than 6 quintuple layers (QL). These findings are characteristic of the SS of a STI and are direct manifestation of strong topological protection against impurities. For samples thinner than 6-QL, STS studies reveal the openup of an energy gap in the SS due to overlaps of wave functions between the surface and interface layers. Additionally, spin-preserving quasiparticle interference wave-vectors are observed, which are consistent with the Rashba-like spin-orbit splitting.

原文English
文章編號00021
期刊EPJ Web of Conferences
23
DOIs
出版狀態Published - 2012
事件2011 Eurasia Pacific Summer School and Conference on Strongly Correlated Electrons - Turunc-Marmaris, Turkey
持續時間: 2011 七月 42011 七月 14

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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