Structure of the (111) surface of bismuth: LEED analysis and first-principles calculations

The surface structure of Bi(111) was investigated by low-energy electron diffraction (LEED) intensity analysis for temperatures between 140 and 313K and by first-principles calculations. The diffraction pattern reveals a (1×1) surface structure and LEED intensity versus energy simulations confirm that the crystal is terminated with a Bi bilayer. Excellent agreement is obtained between the calculated and measured diffraction intensities in the whole temperature range. The first interlayer spacing shows no significant relaxation at any temperature while the second interlayer spacing expands slightly. The Debye temperatures deduced from the optimized atomic vibrational amplitudes for the two topmost layers are found to be significantly lower than in the bulk. The experimental results for the relaxations agree well with those of our first-principles calculation.This work was supported by the American National Science Foundation, Grant No. DMR-0134933, the Danish National Science Foundation, the Basque Country Government, and by the University of the Basque Country.Peer reviewe