Origin, Cause, and Electronic Structure of the Symmetric Dimers of Si(100) at 80 K

Abstract

The characteristics of the apparent symmetric dimers observed in the scanning tunneling microscope (STM) images at low temperatures (20K–200K), far below the symmetric⇔buckled phase transition temperature, were investigated by utilizing the technique applied to fabricate an almost defect free Si(100) surface, the art of atomic manipulation, and current imaging tunneling spectroscopy. We show that the symmetric dimers are observed at metastable regions caused by the surrounding defects, and they appear symmetric as a result of flip-flop motions of buckled dimers.