2008/10/31 by Yasuhiro Niimi, Y. Niimi, H. Kambara +1 · 2 citations
Materials Science · Physics and Astronomy · #Graphene research and applications #Quantum and electron transport phenomena #Surface and Thin Film Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.102.026803
published as Phys. Rev. Lett. 102, 026803 (2009) · 4 pages, 3 figures
openalex publication_date 2009/01/13 · arxiv created 2009/01/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We measured the local density of states of a quasi two-dimensional electron system (2DES) near defects, artificially created by Ar-ion sputtering, on surfaces of highly oriented pyrolytic graphite (HOPG) with scanning tunneling spectroscopy (STS) in high magnetic fields. At valley energies of the Landau level spectrum, we found two typical localized distributions of the 2DES depending on the defects. These are new types of distributions which are not observed in the previous STS work at the HOPG surface near a point defect [Y. Niimi, Phys. Rev. Lett. 97, 236804 (2006).10.1103/PhysRevLett.97.236804]. With increasing energy, we observed gradual transformation from the localized distributions to the extended ones as expected for the integer quantum Hall state. We show that the defect potential depth is responsible for the two localized distributions from comparison with theoretical calculations.