Banca de DEFESA: LUAN MARTINS TORRES DE MORAES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUAN MARTINS TORRES DE MORAES
DATE: 31/07/2023
TIME: 14:00
LOCAL: Através de Videoconferência: https://meet.google.com/cuy-urzi-dgi
TITLE:

Correlated disorder-driven superconductivity in quasi-1D samples

KEY WORDS:

Correlated disorder; Superconductivity; Quasi-1D samples; Disorder strength;
Spatial correlations.

PAGES: 101
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

The recent explosive growth of interest in the phenomenon of interplay between disorder and
superconductivity has been a joint success of theory and experiment. With the aim of improving
the superconducting properties of materials, much of the relevant earlier research has
focused predominantly on the study of the influence of the disorder strength. Consequently,
we now have a clear understanding that an increase in disorder can lead to a remarkable improvement
in the superconductivity figures of merit. For example, recent studies have revealed
an unprecedented disorder-induced rise in the superconductive characteristics of quasi-1D single
crystals made of MoSe chains weakly bound by Na atoms. Anomalous enhancement of
superconductivity due to large structural disorder has also been reported for TaS2 monolayers.
However, in some respects, the theory lags behind. One profound theoretical issue that
has not been given due attention so far is related to the applicability of models of spatially
uncorrelated disorder. That is, the theory of disordered superconductors is almost exclusively
based on spatially uncorrelated disorder, although disorder is almost never completely random
in real systems. In most materials, inhomogeneity is arranged in a certain structure characterized
by spatial correlations. There is a growing appreciation of the fact that such correlations
can qualitatively change the essential properties of many disordered systems.
Recently, an approach to account for disorder correlation has been proposed to study the
zero-temperature superconducting characteristics. Calculations have shown that long-range
correlations change the statistical properties of the superconducting order parameter. Furthermore,
an increase in the degree of correlation in the disorder potential tends to enhance superconducting
correlations. As a result, global superconductivity can be designed to be much
more robust with respect to the disorder strength.
The influence of disorder correlations in samples of quasi-low dimensionality can be even
more significant, as even weak disorder significantly affects the shape resonance effect, which

is responsible for the increase in critical temperatures with decreasing sample size, as shown
earlier.
Motivated by these experimental findings, this thesis investigates the effect of correlated
disorder on the superconducting properties of a nanowire at low temperature. Within the
framework of the Bogoliubov-de Gennes tight-binding formalism, the aim is to understand
the interplay between the effect of disorder correlation and the quasi-low dimensionality of the
superconducting samples.

COMMITTEE MEMBERS:
Externo à Instituição - ANDREY CHAVES - UFC
Presidente - 1130930 - JOSE ALBINO OLIVEIRA DE AGUIAR
Interno - 2378411 - RENE RODRIGUES MONTENEGRO FILHO