Adsorption structure of germanium on the Ru(0 0 0 1) surface

• Published in: Applied surface science 2007-11, Vol.254 (2), p.431-435
• Main Authors: Lu, Y.H., Jia, Y., Zhang, H.J., Song, B., Li, H.Y., Bao, S.N., He, P.
• Format: Article
• Language: English
• Subjects: Ab initio DFT calculation; Adsorption structure; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Density functional theory, local density approximation; Electron states; Exact sciences and technology; Ge/Ru growth system; Methods of electronic structure calculations; Physics; Scanning tunneling microscopy; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.05.084

Coverage-dependent adsorption energy of the Ge/Ru(0 0 0 1) growth system and the geometrical distortions of the most stable adsorption structure are investigated through first-principles calculations within density functional theory. A local minimum in adsorption energy is found to be at a Ge coverage of 1/7 monolayer with a Ru(0 0 0 1)- 21 × 21 - 3 Ge symmetry. Based on this stale superstructure, the scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) images are simulated by means of surface local-density of states (LDOS). The results are consistent well with the STM measurements on the 21 × 21 phase for Ge overlayer on Ru(0 0 0 1). From this stimulation, the relations between the STM images and the lattice distortion are also clarified.