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Study of Large Scale Linear Fringes on Graphite Surface by Scanning Tunneling Microscopy

2007; Institute of Physics; Volume: 46; Issue: 11R Linguagem: Inglês

10.1143/jjap.46.7450

1347-4065

Shyam Kumar Choudhary, Anjan K. Gupta,

Quantum and electron transport phenomena

An unusual pattern on highly oriented pyrolytic graphite surface is observed using scanning tunneling microscope (STM). The pattern is a set of linear fringes originating from a long defect. As one moves away from the defect, the fringes bend in a parabolic fashion and become almost parallel before terminating on a step. The image contrast changes both quantitatively and qualitatively on bias polarity change. The conductance images also show a contrast depending on the bias voltage implying that the pattern is predominantly electronic in nature and it is visible through STM due to inhomogeneous density of states (DOS). Some part of the pattern is also found buried under another graphite layer and the pattern's contrast is reversed across this step. This makes us believe that the observed electronic pattern is due to the physical buckling of a graphite layer.