Reactive rearrangements of step atoms by adsorption and asymmetric electronic states of tetrafluoro-tetracyanoquinodimethane on Cu(100)

Abstract

We investigated the local adsorption structure and electronic states of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) on Cu(100) at low coverage using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). F4-TCNQ molecules, which are preferentially adsorbed at a lower step edge, induce the reactive rearrangements of Cu atoms, including the formation of periodic kinks and step etching. The cyano groups of F4-TCNQ adsorbed at the step edge interact with not only the Cu(100) terrace but also Cu atoms at an upper step edge. This extra interaction results in the asymmetric electronic states in F4-TCNQ species, which are evidenced by STM and STS.