Author ORCID Identifier

https://orcid.org/0000-0001-5582-4515

Semester

Fall

Date of Graduation

2025

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Physics and Astronomy

Committee Chair

Aldo H. Romero

Committee Member

Tudor D. Stanescu

Committee Member

Edward Flagg

Committee Member

Brian Popp

Abstract

The concept of symmetry is central to our understanding of the physical world. Core symmetries—comprising time reversal, charge conjugation, spatial inversion, and rotation—are integral in maintaining essential conservation laws. They also play a critical role in the manifestation of new quantum phases that arise when these symmetries are disrupted. At the heart of contemporary research in condensed matter physics is the exploration of how basic symmetries interact with material imperfections. This examination delves deeply into the ways that inherent symmetrical properties and structural anomalies within materials influence each other, providing crucial insights into the field. This dissertation presents an investigation into enantiomorphic chiral materials alongside La0.7Sr0.3MnO3 (LSMO) thin films highlighting a common underlying principle: the essential role that symmetry and the disruption of symmetry play in determining how these materials function. This theme underscores the pivotal influence that symmetrical properties and their alterations have in influencing the capabilities and behaviors of these materials. Leveraging chemical combinatorics, we uncover a family of chiral crystal spinels with the chemical formula ABZnO4 that display giant optical rotation and altermagnetism candidates. Separately, introducing intercalated magnetic ions in a van der Waals material results in long range helical antiferromagnetic order and undergoes a magnetic transition to a conical antiferromagnetic order through spin-lattice coupling to a Raman active phonon mode. In addition to intrinsic symmetry reduction through crystal chirality, we examine the impact of oxygen vacancy defects in LSMO thin films. Here we find the deterioration of magnetic characteristics seen in experiments attributable to the presence of oxygen vacancies, which serves as a remarkable illustration of the impact that extrinsic symmetry breaking can have, particularly when it manifests as defect-induced disorder. This phenomenon can lead to significant adverse effects on the performance of the material. Integrating these two lines of inquiry offers a multidimensional perspective on engineering advanced spintronic devices. For instance, while chiral materials may offer routes to enhanced control over spin transport through intrinsic electronic chirality, LSMO thin films provide a platform where extrinsic defects, such as oxygen vacancies, need to be minimized or controlled to achieve robust ferromagnetism. In practical device architectures, combining chiral materials with optimized magnetic oxides like LSMO could lead to hybrid systems that exploit the benefits of both intrinsic symmetry-driven properties and defect-engineered functionalities.

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