Efeito de uma barreira cinética em modelos de crescimento de interfaces com mobilidade limitada

• Autor(a) principal: Pereira, Anderson de Jesus
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4264
• topic: Física estatística; Método de Monte Carlo; Filmes finos; Aspereza de superfície; Statistical physics; Monte Carlo method; Thin films; Surface roughness; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA

In thin film growth, morphology is one of the most important characteristics. In particular, the appearance of self-assembled three-dimensional structures, characterized by mounds, with origin attributed to barriers that cause an imbalance between up- and downhill currents in stepped surfaces. In this dissertation we study the effects of the introdution of a kinetic barrier that appears when we include the normal diffusion to the substrate in the migration between different planes in the models ofWolf-Villain and Das Sarma-Tamborenea. The aim is to investigate the morphological changes and growth dynamics of interfaces due to this barrier in one and two-dimensional substrates. In our simulations simulations, we observed interfaces with structures characterized by the presence of mounds, with typical morphological patterns observed in films with self-assembled three-dimensional structures, not observed for the WV and DT models without the kinetic barrier. In the WV and DT models with kinetic barrier in d = 1 + 1 and d = 2 + 1 dimensions, we find that the growth exponent goes to 1=2 in the asymptotic limit. We calculate the ascendent and descendent currents between terraces and determine the average flow of particles in steps per site. We observe a descendent current in the steps for both models, approaching an zero value after a long time, where we would expect a balance between upward and downward particle flow and also saturating the width interface.