Full metadata
Title
Charge Density Wave Engineering in Rare-Earth Tritellurides: Investigating Stability Analysis and Large Area Deposition Technique for Novel Applications
Description
Rare-earth tritellurides (RTe3) are two-dimensional materials with unique quantum properties, ideal for investigating quantum phenomena and applications in supercapacitors, spintronics, and twistronics. This dissertation examines the electronic, magnetic, and phononic properties of the RTe3 family, exploring how these can be controlled using chemical pressure, cationic alloying, and external pressure.The impact of chemical pressure on RTe3 phononic properties was investigated through noninvasive micro-Raman spectroscopy, demonstrating the potential of optical measurements for determining charge density wave (CDW) transition temperatures. Cationic alloying studies showed seamless tuning of CDW transition temperatures by modifying lattice constants and revealed complex magnetism in alloyed RTe3 with multiple magnetic transitions.
A comprehensive external pressure study examined the influence of spacing between RTe3 layers on phononic and CDW properties across the RTe3 family. Comparisons between different RTe3 materials showed LaTe3, with the largest thermodynamic equilibrium interlayer spacing (smallest chemical pressure), has the most stable CDW phases at high pressures. Conversely, CDW phases in late RTe3 systems with larger internal chemical pressures were more easily suppressed by applied pressure.
The dissertation also investigated Schottky barrier realignment at RTe3/semiconductor interfaces induced by CDW transitions, revealing changes in Schottky barrier height and ideality factor around the CDW transition temperature. This indicates that chemical potential changes of RTe3 below the CDW transition temperature influence Schottky junction properties, enabling CDW state probing through interface property measurements.
A detailed experimental and theoretical analysis of the oxidation process of RTe3 compounds was performed, which revealed faster degradation in late RTe3 systems. Electronic property changes, like CDW transition temperature and chemical potential, are observed as degradation progresses. Quantum mechanical simulations suggested that degradation primarily results from strong oxidizing reactions with O2 molecules, while humidity (H2O) plays a negligible role unless Te vacancies exist.
Lastly, the dissertation establishes a large-area thin film deposition at relatively low temperatures using a soft sputtering technique. While focused on MoTe2 deposition, this technique may also apply to RTe3 thin film deposition.
Overall, this dissertation expands the understanding of the fundamental properties of RTe3 materials and lays the groundwork for potential device applications.
Date Created
2023
Contributors
- Yumigeta, Kentaro (Author)
- Tongay, Sefaattin (Thesis advisor)
- Ponce, Fernando (Committee member)
- Drucker, Jeffery (Committee member)
- Erten, Onur (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
323 pages
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.2.N.187414
Level of coding
minimal
Cataloging Standards
Note
Partial requirement for: Ph.D., Arizona State University, 2023
Field of study: Physics
System Created
- 2023-06-06 07:34:14
System Modified
- 2023-06-06 07:34:32
- 1 year 5 months ago
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