Gabriela F. Cabeza

Growth and structure of thin platinum films deposited on Co(0001) studied by low-energy electron diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and scanning tunneling microscopy

Abstract The growth of platinum deposited on Co(0001) at room temperature in the range of submonolayer coverage is described. The evolution of very thin Pt films has been studied using low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and scanning tunneling microscopy (STM). The LEED patterns suggested a coherent epitaxial growth mode for Pt on Co(0001). Evidence for an island growth mode has been confirmed by STM together with step decoration. However, the second and third monolayers start growing before the completion of the first Pt layer. The electronic structure of the Pt deposits exhibited original properties with low Fermi level density of states and valence-band broadening. This is in agreement with theoretical calculations presented in this work.

Role of Van der Waals Forces in Graphene Adsorption over Pd, Pt, and Ni

We report ab initio computations with the Vienna Ab initio Simulation Package (VASP) aimed at elucidating the adsorption mechanism of graphene-like structures on (111) Pd, Pt, and Ni surfaces. To study the adsorption properties, we simulate an already-formed graphene layer. We present a comparative discussion of the graphene interactions with the three metals, focusing on the very particular adsorption of graphene over Pd.

The H-FeCo interaction in BCC structure : An ASED-MO approach

Abstract The semiempirical atom superposition and electron delocalization molecular orbital (ASED-MO) theory was used to study the H-FeCo interaction. Calculations were carried out using clusters of the type Fe 45 Co 16 and Fe 39 Co 14 for normal and dislocated structures respectively, simulating both the adsorption and absorption of a hydrogen atom on/in the (100) face and in the (100) dislocation. The results indicate that in general the H-FeCo interaction is stronger for the dislocated structure. The available volume for the atomic H is greater as a consequence of the extra plane of atoms. The relative stability of this configuration was also compared for clusters representing normal and dislocated FeCo structures and with Co vacancies.