Dissertação
Estudo de primeiros princípios de nanofios de inas submetidos a tensões extremas
Fecha
2015-03-30Registro en:
SAMPAIO, Leonardo Fernandes. First principles study of inas nanowires subjected
to extreme stress. 2015. 58 f. Dissertação (Mestrado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2015.
Autor
Sampaio, Leonardo Fernandes
Institución
Resumen
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.