Scanning tunneling microscopy observation of Pb-induced superstructures on Si(557)
- Institute of Physics and Applied Physics and Center for Atomic Wires and Layers, Yonsei University, 134 Shinchon, Seoul 120-749 (Korea, Republic of)
Pb-induced superstructures on Si(557) are investigated by low-energy-electron diffraction (LEED) and scanning tunneling microscopy (STM). Using an indirect heating method, we have succeeded in obtaining almost perfect single-domain LEED patterns of one-dimensional wire (chain) structures, so called {alpha}x2 and {beta}x2 phases. Careful LEED analysis and STM investigation reveal that these phases are formed on the (223) and (112) facets, respectively. The {alpha}x2 phase has regular bundles of triple wires at low annealing temperature but wider bundles through step bunching after a higher temperature annealing. Along the wires of the {alpha}x2 phase, which was recently reported to exhibit a transition between one-dimensional (1D) metallic and 2D semiconducting conductance, a clear commensurate x2 modulation is observed at 78-120 K in contrast to the incommensurate and disordered structure reported previously. A tentative atomic structure model of the {alpha}x2 phase is proposed based on the dense Pb overlayers on (111) and (223) facets. The details of the STM images of the {beta}x2 phase are discussed.
- OSTI ID:
- 21052733
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 16 Vol. 76; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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