The results of an angle-resolved photo-emission study of the driving mechanism in (001) surface reconstruction was reported. It was found, for the first time, that there was a remarkable change in the shapes of Fermi contours upon cooling. This revealed that there was a significant nesting at 6.5/nm, which extended by 3/nm perpendicular to the ¯ axis. The results suggested that the reconstruction occurred via Peierls-type instabilities, with significant matrix element effects.

J.W.Chung, K.S.Shin, D.H.Baek, C.Y.Kim, H.W.Kim, S.K.Lee, C.Y.Park, S.C.Hong, T.Kinoshita, M.Watanabe, A.Kakizaki, T.Ishii: Physical Review Letters, 1992, 69[15], 2228-31