Yoshinori Okada, Wenwen Zhou, Chetan. Dhital, D. Walkup, Ying Ran, Z. Wang, Stephen D. Wilson, V. Madhavan
Topological insulators represent a new state of matter where the topological nature of the bulk bands dictates the existence of a surface state with unique properties. These materials are predicted to host exotic states such as Majorana Fermions and 1D chiral modes, many of which require a delicate tuning of the surface state properties near the Dirac point by doping or gating. Using scanning tunneling microscopy (STM) on the prototypical topological insulator Bi2Te3, we have discovered one-dimensional topographic stripes, which induce spatially modulated changes in the surface state dispersion close to the Dirac point. In a magnetic field this results in a striped pattern of spatial regions with alternating filling fractions. The observed modulation dictates the existence of topological 1D chiral modes at the boundaries between stripes when chemical potential is tuned properly, and provides a platform for the experimental realization of 1D dissipationless quantum wires in topological insulators. Our discovery that the slope of the surface state dispersion close to the Dirac point is modulated over nanometer length scales by an intrinsic topographic route represents a new paradigm for controlling the properties of Dirac electrons.
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http://arxiv.org/abs/1203.0020
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