| AVS 66th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Wednesday Sessions |
| Session EM+2D+AS+MI+MN+NS+TF-WeM |
| Session: | Nanostructures and Nanocharacterization of Electronic and Photonic Devices |
| Presenter: | Shirley Chiang, University of California, Davis |
| Authors: | S. Chiang, University of California, Davis R.K. Xie, Donghua University, China H.Z. Xing, Donghua University, China T.S. Rahman, University of Central Florida C.Y. Fong, University of California, Davis |
| Correspondent: | Click to Email |
Two ad-atoms of Au and Ir adsorbed, respectively, on the Ge(110) surface are studied by a first-principles algorithm based on density functional theory. The surface is modeled by a slab consisting of 108 Ge atoms with a 10 Å vacuum region. Hydrogen atoms are used to saturate the dangling orbitals at the other side of the vacuum region. Two cases of Au adsorption and one case of Ir are reported. The case of Ir has a large binding energy because of its small atomic size compared with the Ge atom, and the partially filled d-states. The total energy for each case is given, as are the energies for removing one ad-atom at a time and also both ad-atoms. The binding energy of each case is obtained by simply taking the energy difference between these configurations; this method is more realistic because the experimental data measured by LEEM and STM indicate that the collective motions of the ad-atoms do not allow the surface to relax to its equilibrium state.[1] For a large separation in the case of two Au atoms, there is a smaller binding energy than for one ad-atom. This can relate to the fact that the collective motions seen experimentally do not happen at a full monolayer coverage of ad-atoms.[1] Additional comparisons will be made to an atomic model for Ir/Ge(111) from STM measurements.[2]
[1] B. H. Stenger et al., Ultramicroscopy, 183, 72 (2017).
[2] M. van Zijll et al., Surf. Sci. 666, 90, (2017).
Support from NSF DMR-1710748 (SC, CYF); NSF DMR-1710306 (TSR); National Natural Science Foundation of China Grants 61376102, 11174048 and computational support from Shanghai Supercomputer Center (RKX, HZX).