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- Joco, V., et al.
(författare)
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Surface phase transition and electronic structure of c(5 root 2 x root 2)R45 degrees-Pb/Cu(100)
- 2006
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Ingår i: Proceedings of the 23th European Conference on Surface Science (Surface Science). - : Elsevier BV. - 0039-6028. ; 600:18, s. 3851-3855
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Konferensbidrag (refereegranskat)abstract
- The c(5 root 2 x root 2)R45 degrees-Pb/Cu(100) surface phase is investigated by means of angle resolved ultraviolet photoemission and low energy electron diffraction in the temperature range between 300 and 550 K. We identify and characterize a temperature-induced surface phase transition at 440 K from the room temperature e(5 root 2 x root 2) R45 degrees phase to a (root 2 x root 2)R45 degrees structure with split superstructure spots. The phase transition is fully reversible and takes place before the two-dimensional melting of the structure at 520 K. The electronic structure of the split (root 2 x root 2)R45 degrees phase is characterized by a metallic free-electron like surface band. This surface band is backfolded with c(5 root 2 x root 2)R45 degrees periodicity phase at room temperature, giving rise to a surface band gap at the Fermi energy. We propose that a gain in electronic energy explains in part the stability of the c(5 root 2 x root 2)R45 degrees phase. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
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| 3. |
- Martinez-Blanco, J, et al.
(författare)
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Surface phase diagram and temperature induced phase transitions of Sn/Cu(100)
- 2006
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Ingår i: Proceedings of the Eight International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures and the Thirteenth International Congress on Thin Films - ACSIN8/ICTF13 (Applied Surface Science). - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 252:15, s. 5331-5334
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Konferensbidrag (refereegranskat)abstract
- Room temperature deposition of Sn on Cu(100) gives rise to a rich variety of surface reconstructions in the submonolayer coverage range. In this work, we report a detailed investigation on the phases appearing and their temperature stability range by using low-energy electron diffraction and surface X-ray diffraction. Previously reported reconstructions in the submonolayer range are p(2 x 2) (for 0.2 ML), p(2 x 6) (for 0.33 ML), (3 root 2 x root 2)R45 degrees (for 0.5 ML), and c(4 x 4) (for 0.65 ML). We find a new phase with a ((-4)(0) (2)(4)) structure for a coverage of 0.45 ML. Furthermore, we analyze the temperature stability of all phases. We find that two phases exhibit a temperature induced reversible phase transition: the (3 root 2 x root 2)R45 degrees phase becomes (root 2 x root 2)R45 degrees phase above 360 K, and the new ((-4)(0) (2)(4)) phase becomes p(2 x 2) also above 360 K. The origin of these two-phase transitions is discussed. (c) 2005 Elsevier B.V. All rights reserved.
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