LEED and Ab-Initio Study of the SmSi(111)-3x2 Reconstruction

The Si(111)3x2-Sm reconstruction that has been observed by STM produces a 3x1 pattern when viewed using LEED [1]. It has been suggested that similar behaviour for Si(111)3x2-Ba is due to the interference of the emergent electron amplitudes between adjacent registry shifted unit cells [2]. We have gathered LEED I(V) curves from this surface and here we present a quantitative comparison of these with a structural model that has been suggested in the literature [3] and with the results of our own ab-initio calculations done using the CASTEP [4] code. \\ \ \\ {[}1{]} {C. Wigren {\it et al},{\it Phys. Rev. B.},{\bf 48} (1993) 11014-11021}\\ {[}2{]} {J. Schafer {\it et al}, {\it Phys. Rev. B.}, {\bf 67} (2003) 85411-85415}\\ {[}3{]} {E. Ehret {\it et al}, {\it Surf. Sci.}, {\bf 569} (2004) 23-32}\\ {[}4{]} {M. D. Segall {\it et al}, {\it J. Phys.: Cond. Matt.}, {\bf 14} (2002) 2717-2743} \\