Superconductivity in Multi-Band and Disordered Systems

We propose that a clean array 4He atoms is a self-generated Mott insulator, that is, the 4He atoms constitute the lattice as well as the charge carriers. With this assumption, we are able to interpret the textbook defect-driven supersolids as excitations of either the lower or upper Hubbard bands. In the experiments at hand, disorder induces a closing of the Mott gap through the generation of mid-gap localized states at the chemical potential. Depending on the magnitude of the disorder, we find that the destruction of the Mott state takes place for d + z > 4 either through a Bose glass phase (strong disorder) or through a direct transition to a superfluid (weak disorder). For d + z < 4, disorder is always relevant. The critical value of the disorder that separates these two regimes is shown to be a function of the boson filling, interaction and the momentum cut off. We apply our work to the experimentally observed enhancement 3He impurities has on the onset temperature for the missing moment of inertia. We find quantitative agreement with experimental trends. (Abstract shortened by UMI.).

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Wu, Jiansheng

Contributors dc:contributor

• Cooper, S. Lance

• Physics, Low Temperature

Language dc:language

eng

Identifier

(MiAaPQ)AAI3395543

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/80625