Electronic Theses and Dissertations

Identifier

6414

Author

Zhi Song

Date

2019

Date of Award

4-29-2019

Document Type

Thesis

Degree Name

Master of Science

Major

Physics

Concentration

Computational Physics

Committee Chair

Xiao Shen

Committee Member

Jingbiao Cui

Committee Member

Mohamed Laradji

Abstract

A number of experimental studies have reported that phosphorsilicate glass (PSG) exhibits switchable electrical polarization like ferroelectric materials. However, the mechanism of electrical dipole switching is not understood. The present work constructs an atomistic model of the switchable polarization in PSG by mainly using a bond-switching algorithm. In addition, the density functional theory, the BFGS algorithm, and molecular dynamics were implemented to optimize the structures. The initial system of amorphous silicon dioxide used to construct models of PSG was generated by the bond-switching algorithm and the Metropolis Monte Carlo method. The most likely structures of PSG were obtained to investigate the polarization switching. A plausible mechanism, unveiled to explain the dipole switching, is based on the migration of an oxygen atom causing the transition between a nonpolarized state and a polarized state. Finally, we propose a feasible approach of decreasing the energy barrier of switching for practical applications.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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