Abstract

Perovskite oxide heterostructures have key applications in technologies such as solid oxide fuel cells (SOFCs), batteries, solar cells, etc. because of novel properties at the interface. Although it is well-known that this is caused by lattice mismatch and misfit dislocations, the role defects play in enhancing certain properties is unknown. We have investigated SrTiO$_3$ (STO) and BaZrO$_3$ (BZO) structures because they both experience novel oxygen vacancy formation which is desired for high ionic conductivity applications such as the thin film electrolyte of a SOFC. Through explicit density functional theory calculations of four STO/BZO interfaces, electron migration, oxygen vacancy formation energies, and density of states (DOS) plots have been analyzed and compared. From identifying the most optimal interfaces for ion transport, we have developed a method of predicting which solid oxide heterostructures take the most advantage of strain relaxation and misfit dislocations. Out of the four orientations of the STO/BZO heterostructure, doped ZrO$_2$-TiO$_2$ calculations contained sites of spontaneous vacancy formation while the orientations BaO-SrO and SrO-ZrO$_2$ have been identified with defects that are undesirable for vacancies. Discussion is offered on the extent that ground state electronic structures can guide material analysis for nanoionic devices.

Library of Congress Subject Headings

Oxide minerals; Solid oxide fuel cells; Electronic structure

Publication Date

8-2023

Document Type

Thesis

Student Type

Graduate

Degree Name

Physics (MS)

Department, Program, or Center

School of Physics and Astronomy (COS)

Advisor

Michael Pierce

Advisor/Committee Member

Ke Xu

Advisor/Committee Member

Gregory Howland

Campus

RIT – Main Campus

Plan Codes

PHYS-MS

Download

Share

COinS