Strong electronic perturbation of the Cu{111} surface by 7,7′,8,8′-tetracyanoquinonedimethane

• Published in: Surface science 1998-12, Vol.419 (1), p.12-23
• Main Authors: Kamna, M.M, Graham, T.M, Love, J.C, Weiss, P.S
• Format: Article
• Language: English
• Subjects: Aromatics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Copper; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Scanning tunneling microscopy; Self-assembly; Solid surfaces and solid-solid interfaces; Solid-fluid interfaces; Structure and morphology; thickness; Surface and interface electron states; Surface electronic phenomena; Surface states, band structure, electron density of states; Surface structure; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(98)00636-0

We have imaged 7,7′,8,8′-tetracyanoquinonedimethane (TCNQ) on the Cu{111} surface at 77 K using scanning tunneling microscopy. TCNQ forms molecular chains along the steps at extremely low surface coverages. Oriented adsorption of TCNQ occurs along both the top and the bottom of the Cu steps in which the long molecular axis is parallel to the steps. Monolayer films on the terraces nucleate from TCNQ adsorbed at the steps. Ordered domains of TCNQ coexist with regions of disorder within the monolayer. We find that TCNQ strongly and anisotropically perturbs the local density of electronic states on the Cu{111} surface. These molecular perturbations of the surface determine the ordering of TCNQ on the Cu terraces.