The geometric structure of the α-Ga(010)-(1 x 1) room temperature structure and its (2√2 x √2)R45° reconstruction below 232K were determined using low-energy electron diffraction structure analysis. The room temperature structure conformed to the cut-dimer model, forming a two-dimensional metallic structure with only minimal lateral displacements of the atoms. The topmost interlayer distance was 1.53Å, corresponding to a spacing expansion of 2% from the bulk. In the low-temperature structure, the surface atoms shift to dimerize within the top two layers, resulting in a network of mostly covalent bonds, which formed both parallel and perpendicular to the surface plane. The bond lengths of some of these dimers were about 10% shorter than the bond length found in the α-Ga bulk and were thus shorter than any Ga-Ga bonds reported so far.

A LEED Structural Analysis of the (1 x 1) α-Ga(010) Surface Reconstruction - Room Temperature and (2√2x√2)R45° Low-Temperature Structures. S.Moré, E.A.Soares, M.A.Van Hove, S.Lizzit, A.Baraldi, C.Grütter, J.H.Bilgram, P.Hofmann: Physical Review B, 2003, 68[7], 075414 (10pp)