Estudo de primeiros princípios de nanofios de inas submetidos a tensões extremas

• Autor(a) principal: Sampaio, Leonardo Fernandes
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/9249
• topic: Nanofios; Modulo de young; Rupturas; Nanowires; Young modulus; Rupture; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA

The ability to manipulate materials at the atomic scale turn it possible to look for materials at the nanoscale that can supersede the performance of their bulk counterparts in specific tasks. Nanowires, due to their unique structural characteristics, are natural candidates for electric or heat conducting devices. When these nanowires take part of a circuit, they can subjected to an external stress that can change their intrinsic properties. In this work, we will be studying the mechanical and electronic behavior of narrow InAs nanowires, with different diameters, when subjected to extreme external stress. Our calculations use the Density Functional Theory, and the local density approximation to the exchange and correlation potential, as implemented in the VASP code. Our results reveal that the InAs nanowires exhibit a mechanical behavior which depends on the external stress and the nanowire diameter. For the narrowest diameter, it shows an elastic behavior followed by the rupture of the wire. As the nanowires turn thicker, different responses to the external stress take place. When the first chemical bonds are broken, the nanowire changes between elastic behaviors with different Young modulus. When more and more chemical bonds are broken (for the thicker nanowires), the nanowires show a plastic behavior, before the rupture. For each of these mechanical regimes, the electronic band structure of the nanowires is also analysed.