Structure and morphology of the Ag/MgO(001) interface during in situ growth at room temperature

摘要: The structure and morphology of Ag deposits grown at room temperature on high-quality MgO(001) surfaces have been investigated in situ, from 0.2 to 300 equivalent monolayers (ML) deposited. Surface x-ray diffraction grazing incidence small angle scattering parallel perpendicular the surface were combined. Nucleation, growth, coalescence islands are found ML. average in-plane width, height, separation growing deduced reproduce well Mg $1s$ photoemission spectroscopy spectrum previously reported by other authors. height over width ratio is $\ensuremath{\sim}0.37\ifmmode\pm\else\textpm\fi{}0.05$ all stages deposit. grows cube-on-cube epitaxy with respect substrate. A very unusual evolution state strain increasing amount deposited observed. Below 4\char21{}6 ML (island smaller than 90 \AA{}), coherent MgO. 1 35 they their bulk lattice parameter, between 4 become more strained MgO substrate, an parameter intermediate those Around ML, reach a critical size misfit dislocations introduced edges. Above 30 film almost continuous, interfacial reorder form square network, oriented along 〈110〉 directions. Stacking faults appear this stage. twinned also starts grow around This following introduction interpreted basis one-dimensional Frenkel-Kontorova model involving weak Ag-MgO interaction corrugation interatomic potential. Quantitative measurements analysis crystal truncation rods (CTR's) during growth shown provide different structural parameters interface that important for theoretical calculation, especially epitaxial site, above oxygen atoms distance $(2.52\ifmmode\pm\else\textpm\fi{}0.1\AA{}).$ origin interference CTR's discussed according Ag.