Publication: Nature of the low-temperature 3 x 3 surface phase of Pb/Ge(111)
Loading...
Official URL
Full text at PDC
Publication Date
1999-03-22
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
American Physical Society
Citations
Exportar
Abstract
The structure of the low-temperature 3 X 3 surface phase of Pb/Ge(111) has been determined by surface x-ray diffraction experiments. Analysis of the data reveals that the Pb layer exhibits a vertical corrugation of similar to 0.4 Angstrom, affecting also the two top Ge layers. Significant distortions are found down to the third Ge layer. This structural model supports that the 3 X 3 ground state can be best described as a cooperative distortion stabilized by a gain in electronic energy. [S0031-9007(99)08749-9].
Description
© 1999 The American Physical Society.
This work was financed by DGES (Spain) (Grants No. PB-97-0031 and No. PB-97-1199). We thank the staff of ESRF for experimental support and X. Torrelles, F. Flores, E. Tosatti, and S. Modesti for fruitful discussions. A. M. thanks Eusko Jaurlaritza for financial support.
UCM subjects
Unesco subjects
Keywords
Citation
[1] B. N. J. Persson, Surf. Sci. Rep. 15, 1 (1992).
[2] J. Carpinelli et al., Nature (London) 381, 398 (1996).
[3] J. S. Pedersen et al., Surf. Sci. 189y190, 1048 (1987).
[4] J. M. Carpinelli et al., Phys. Rev. Lett. 79, 2859 (1997).
[5] A. Goldoni and S. Modesti, Phys. Rev. Lett. 79, 3266 (1997).
[6] A. P. Baddorf et al., Phys. Rev. B 57, 4579 (1998).
[7] A. Mascaraque et al., Phys. Rev. B 57, 14 758 (1998).
[8] R. I. G. Uhrberg and T. Balasubramanian, Phys. Rev. Lett. 81, 2108 (1998).
[9] J. Avila et al., Phys. Rev. Lett. 82, 442 (1999).
[10] R. Feidenhans’l, Surf. Sci. Rep. 10, 105 (1989).
[11] S. Ferrer and F. Comin, Rev. Sci. Instrum. 66, 1674 (1995).
[12] The lateral displacements of 1–6 atoms have roughly p 3 symmetry. This explains the smaller intensity of 3 3 3 fractional rods at low l with respect to p 3 fractional rods.
[13] A. Mascaraque et al. (to be published).
[14] P. N. Keating, Phys. Rev. 145, 637 (1966).
[15] The symmetry of the ideal p 3 structure is p31m. Because of these displacements, the symmetry of the 3 3 3 model is reduced to p3.
[16] The three Pb-Ge clusters relaxed independently in the final refinement. The two clusters moving downwards did not reach exactly the same height, and Pb atoms exhibit a small lateral displacement.
[17] The origin of the preferential strain is traced back from the charge-sensitive contours of Ref.
[18]. The p 3-PbyGes111d surface state (distorted in the 3 3 3 phase) is distributed not only above Pb atoms but also at the bonds between the first and second Ge bilayers where we find the largest stretching.
[18] K. Würde, P. Krüger, A. Mazur, and J. Pollmann, Surf. Rev. Lett. 5, 105 (1998).
[19] F. Ancilotto, A. Selloni, and E. Tosatti, Phys. Rev. B 43, 14 726 (1991).
[20] J. Avila et al. (to be published).