Determinação de estados eletronicos de superficie em metais de transição
AUTOR(ES)
Alexandre Abdalla Araujo
DATA DE PUBLICAÇÃO
2002
RESUMO
In recent years, research in metallic systems with two-dimensional symmetry such as thin films, surfaces and multi-layers has been focused primarily on the transition metais, because of their interesting properties and their technological importance. The aim of this dissertation is to study the existence and characterization of electronic surface states for a class of transition metais having a body-centered cubic structure - Tungstein, Molibdenum, Tantalum and Niobium - in the [100], [110] and [111] cleavage. Transition-metal surfaces are much more difficult to treat theoretically because of the coexistence of the localized d electrons and the delocalized sp electrons. Most of developed methods to calculate, self-consistently, the electronic structure of these systems, require perfect two-dimensional symmetry. The electronic structure calculation were carried out using the RS-LMTO-ASA (Real Space - Linear Muffin-Tin Orbital - Atomic Sphere Approximation) formalism, which is based on the standard LMTO-ASA approach and uses the recursion method to solve the eigenvalue problem in real space. The spectral density of states and electronic surface states are obtained by a Green function formalism with the aid of the transfer matrix method. Our results for W(100), Mo(100) and W(110) are in good agreement with experimental observations and theoretical dates found in the literature
ASSUNTO(S)
tantalo metais de transição molibdenio superficies (fisica) niobio tungstenio
ACESSO AO ARTIGO
http://libdigi.unicamp.br/document/?code=vtls000290004Documentos Relacionados
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