Structural model for the metal-induced Si(111)3 x 1 reconstruction

We present a structural model for the metal-induced Si(111)3[times]1 reconstruction. Fivefold Si rings form one-dimensional [pi]-bonded chains along [l angle]1[bar 1]0[r angle]. These chains are separated by empty channels that can accommodate 1/3 monolayer of metal atoms. We propose that the [pi]-bonded chains undergo a strong disturbance resulting in the formation of alternating dimers consistent with published scanning tunneling microscope images [K. J. Wan [ital et] [ital al]., Phys. Rev. B 46, 13 635 (1992)]. Unlike previous models, this model accounts for most experimental observations, including a large band gap and chemical passivation.