Dynamical fluctuations as the origin of a surface phase transition in Sn/Ge(III)

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The Sn/Ge(111) interface has been investigated across the 3 x 3 -->, root 3 x root 3 R30 degrees phase transition using core level and valence band photoemission spectroscopies. We find, both above and below the transition, two different components in the Sn 4d core level and a bond splitting in the surface state crossing the Fermi energy. Theoretical calculations show that these two effects are due to the existence of two structurally different kinds of Sn atoms that fluctuate at room temperature between two positions and are stabilized in a 3 x 3 structure at low temperature.
© 1999 The American Physical Society. This work was financed by DGICYT (Spain) (Grants No. PB-97-0031, No. PB-97-1199, and No. PB92–0168C). We thank the European Union (A. M. and E. G. M.) and Eusko Jaurlaritza (A. M.) for financial support.
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[1] B. N. J. Persson, Surf. Sci. Rep. 15, 1 (1992). [2] J. Carpinelli et al., Nature (London) 381, 398 (1996). [3] T. Ichikawa, Solid State Commun. 46, 827 (1983). [4] R. Feidenhans’l et al., Surf. Sci. 178, 927 (1986). [5] E. Tosatti, in Electronic Surface and Interface States in Metallic Systems, edited by E. Bertel and M. Donath (World Scientific, Singapore, 1995), and references therein. [6] S. D. Kevan, J. Electron Spectrosc. Relat. Phenom. 75, 175 (1995), and references therein. [7] J. M. Carpinelli et al., Phys. Rev. Lett. 79, 2859 (1997). [8] A. Goldoni and S. Modesti, Phys. Rev. Lett. 79, 3266 (1997). [9] A. P. Baddorf et al., Phys. Rev. B 57, 4579 (1998). [10] A. Mascaraque et al., Phys. Rev. B 57, 14 758 (1998). [11] For a recent review, see N. Mårtensson and A. Nilsson, J. Electron. Spectrosc. Relat. Phenom. 75, 209 (1995). [12] M. Göthelid et al., Surf. Sci. 328, 80 (1995). [13] Spin-orbit splitting (1.04 eV) and branching ratio (0.7 eV) are taken from a thicker Sn film. [14] S. B. DiCenzo et al., Phys. Rev. B 31, 2330 (1985). [15] A. A. Demkov et al., Phys. Rev. B 52, 1618 (1995). [16] CETEP, L. J. Clarke, I. Stich, and M. C. Payne, Comput. Phys. Commun. 72, 14 (1992). [17] We used 16 special k-points in the Brillouin zone. Tests with 4, 16, and 36 special k-points show that the results are well converged. A PW cutoff of 12 Ry has been used; increasing the cutoff to 15 Ry changes the energy differences in less than 1 meV. [18] O. Pankratov and M. Scheffler, Phys. Rev. Lett. 70, 351 (1993). [19] A. Levy–Yeyati et al., Appl. Surf. Sci. 104/105, 248 (1996). [20] E. Landemark et al., Phys. Rev. Lett 69, 1588 (1992). [21] P. C. Weakliem, G. W. Smith, and A. Carter, Surf. Sci. 232, L219 (1990). [22] E. Pehlke and M. Scheffler, Phys. Rev. Lett. 71, 2338 (1993). [23] A. Mascaraque et al. (to be published).