Publication Date

2019

Document Type

Dissertation/Thesis

First Advisor

Xiao, Zhili

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Physics

Abstract

ZrTe5 is a topological material that is predicted to have a strain or temperature induced phase transition from a topological insulator state into a Weyl/Dirac semimetal state. In this study I find that there is insufficient evidence to support the claims for the existence of such a phase transition. I performed magnetoresistivity measurements using a Quantum Design Physical Properties Measurement System (PPMS) to measure the transverse and longitudinal resistivities at various temperatures and different strengths and orientations of the magnetic field. The measurement results were analyzed using OriginPro to determine the carrier mobility and density and to determine the temperature and magnetic field dependencies of the magnetoresistivity and magnetoconductance in the material. I conducted numerical calculations to determine the Fermi surface and the band structure of ZrTe5. The calculations were performed in XCrysDen, CASTEP and the VASP package. I then compared my results with those in the literature to test the existing theories and to determine whether or not ZrTe5 is a Weyl/Dirac semimetal.

I found that the magnetotransport behavior used as evidence for existence of 2nd order phase transition in ZrTe5 could be explained by an alternative mechanism, therefore in order to verify the categorization of the material additional research must be performed.

Extent

54 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

Download

Share

COinS