IFIS - LITORAL   24734
INSTITUTO DE FISICA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
An STM and Monte Carlo study of the AlF3 ¯lm growth on Cu(111)
Autor/es:
ADRIANA CANDIA; LILIANA GÓMEZ; R. A. VIDAL; J.FERRÓN; M. C. G. PASSEGGI(JR)
Lugar:
Foz de Iguazú
Reunión:
Congreso; XXXVIII Encontro Nacional de Física da Matéria Condensada; 2015
Institución organizadora:
Sociedad Brasilera de Física
Resumen:
In this work, we studied the AlF3 films growth on Cu(111) at room temperature by means of Scanning Tunnelling Microscopy, Limited Diffusion Aggregation and Metropolis Monte Carlo simulations with the aim ofunderstanding the growth characteristic features based on kinetic and geometric factors. As well, we compare these results with previous ones obtained on Cu(100). The growth of AlF3 sub-monolayers on Cu(111) shows more differences than similarities regarding to the deposition on Cu(100). In both cases, we observe the formation of fractal islands, with very corrugated surfaces and similar heights, 0.25-0.30 nm. The step-edges on Cu(111) are not completely decorated as it is in the case of Cu(100), even at large coverages (> 0.7 ML).The islands are larger in size (this gives longer average distances) and consequently its density smaller. These experimental results are supported by Limited Diffusion Aggregation and Metropolis Monte Carlo calculations.The MMC calculation results show similarities with those of Cu(100) as far as isolated molecules and reconstructed bi-molecules is concerned. While the first ones show an isotropic diffusion by hopping, the bi-molecules diffuse over the surface along privilege directions, showing as well an important change in the diffusion length (2 magnitude orders in the number of MMC steps). Then, when the bi-molecules are formed, they move along the three directions relative to the simmetry axis of the crystal triangular lattice; similar results have been observedfor Cu(100), but in that case only along the two directions of simmetry of the crystal square lattice. Thus, on the Cu(111), when the reconstructed bi-molecules are formed, the potentiality of receiving new contributions is 50 % higher, justifying the larger sizes and smaller surface density of the islands observed in the experiments.While the characteristic of the (100) copper face step-edges appears to be nucleating, the (111) copper face step-edges seem to be of a repulsive nature.
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