Ivan Viti

Publication Date

2016

Document Type

Dissertation/Thesis

First Advisor

Glatz, Andreas

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Physics

LCSH

Nanostructures; Superconductivity

Abstract

There are many condensed matter problems which are too complicated for analytical solutions. Complex functions such as the Ginzburg-Landau equation for superconductors can not be studied analytically for mesoscopic phenomena. Similarly, a thorough understanding of variable range hopping in electrons requires a new Monte-Carlo algorithm. With this in mind we computationally study two cases of condensed matter physics, pinning vortices in superconductors and thermoelectrics in artificial nanosolids. Vortex-vortex interactions and vortex-inclusion interactions are not fully understood analytically. These analytical calculations become near-impossible when taken to mesoscopic scales. Applied temperature, magnetic field, or currents only serve to complicate the system. Yet these are all factors whose effects need to be well understood before large scale applications can be implemented. Here we report two geometry-based strategies, the effect of vortex-inclusion matching on the effective resistance, and a novel funnel system for jamming the vortices. Both of these strategies are designed to reduce energy dissipation by moving vortices. In the second part, we study thermoelectric effects in artificial nanosolids. To this end, a parallel optimized algorithm for simulation of variable-range hopping of electrons in nanosolids was designed and implemented. We exploit the similarities between granule hopping and electrons in a Coulomb glass to get a better analytical understanding. We benchmark this code using known analytical results in limiting cases. We then make predictions for Seebeck coefficients in mixed conductor-semiconductor granular nanosolids.

Comments

Advisors: Andreas Glatz.||Committee members: Omar Chmaissem; Zhili Xiao.||Includes bibliographical references.||Includes illustrations.

Extent

x, 87 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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