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arXiv · 0704.3713

Shear-strain-induced Spatially Varying Super-lattice Structures on Graphite studied by STM

S. K. Choudhary·A. K. Gupta
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Abstract

We report on the Scanning Tunneling Microscope (STM) observation of linear fringes together with spatially varying super-lattice structures on (0001) graphite (HOPG) surface. The structure, present in a region of a layer bounded by two straight carbon fibers, varies from a hexagonal lattice of 6nm periodicity to nearly a square lattice of 13nm periodicity. It then changes into a one-dimensional (1-D) fringe-like pattern before relaxing into a pattern-free region. We attribute this surface structure to a shear strain giving rise to a spatially varying rotation of the affected graphite layer relative to the bulk substrate. We propose a simple method to understand these moire patterns by looking at the fixed and rotated lattices in the Fourier transformed k-space. Using this approach we can reproduce the spatially varying 2-D lattice as well as the 1-D fringes by simulation. The 1-D fringes are found to result from a particular spatial dependence of the rotation angle.

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S. K. Choudhary, A. K. Gupta. 2008-01-04. Shear-strain-induced Spatially Varying Super-lattice Structures on Graphite studied by STM. https://doi.org/10.1088/0953-8984%2F20%2F22%2F225008

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