摘要
The wave function of Dirac fermions is a two-component spinor. In graphene, a one-atom-thick film showing two-dimensional Dirac-like electronic excitations, the two-component representation, reflects the amplitude of the electron wave function on the A and B sublattices. This unique property provides unprecedented opportunities to image the two components of Dirac fermions spatially. Here, we report atomic resolution imaging of two-component Dirac-Landau levels in gapped graphene monolayers by scanning tunneling microscopy and spectroscopy. A gap of about 20 meV, driven by inversion symmetry breaking by the substrate potential, is observed in the graphene sheets on both SiC and graphite substrates. Such a gap splits the n=0 Landau level (LL) into two levels, 0+ and 0-. We demonstrate that the amplitude of the wave function of the 0+ LL is mainly on the A sites and that of the 0- LL is mainly on the B sites of graphene, characterizing the internal structure of the spinor of the n=0 LL. This provides direct evidence of the two-component nature of Dirac fermions.
源语言 | 英语 |
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文章编号 | 165420 |
期刊 | Physical Review B - Condensed Matter and Materials Physics |
卷 | 92 |
期 | 16 |
DOI | |
出版状态 | 已出版 - 16 10月 2015 |
已对外发布 | 是 |