Nature of the low-temperature 3 x 3 surface phase of Pb/Ge(111)

© 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.
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].
DGES (Spain)
Eusko Jaurlaritza
Depto. de Física de Materiales
Fac. de Ciencias Físicas
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