We observed atomic resolution images of the Si(1 0 0) surface at 5 K using low-temperature noncontact atomic force microscope (LT-NC-AFM). Si(1 0 0) surface shows almost the asymmetric dimers structure, except for the symmetric dimers structure near the defects. The asymmetric dimers are mainly c(4 x 2) structure with antiparallel zigzag pattern and partly p(2 x 2) structure with parallel zigzag pattern. (C) 2002 Published by Elsevier Science B.V.