The atomic structure and lattice dynamics of epitaxial BeTe(001) thin films are derived from surface x-ray diffraction and Raman spectroscopy. On the Te-rich BeTe(001) surface [1 (1) over bar0]-oriented Te dimers are identified. They cause a (2 X 1) superstructure and induce a pronounced buckling in the underlying Te layer. The Be-rich surface exhibits a (4 X 1) periodicity with alternating Te dimers and Te-Be-Te trimers. A vibration eigenfrequency of 165 cm(-1) is observed for the Te-rich surface, while eigenmodes at 157 and 188 cm(-1) are found for the Be-rich surface. The experimentally derived atomic geometry and the vibration modes are in very good agreement with the results of density functional theory calculations.
Kumpf, C., Müller, A., Weigand, W., Umbach, E., Wagner, J., Wagner, V., Gundel, S., Hansen, L., Geurts, J., Bunk, O., Zeysing, J. H., Wu, F., & Johnson, R. L. (2003). Analysis of structure and vibrational dynamics of the BeTe(001) surface using X-ray diffraction, Raman spectroscopy, and density functional theory. Physical Review B Condensed Matter, 68(3), 035339. https://doi.org/10.1103/PhysRevB.68.035339