Navigating the Intermetallic Landscape: From Quasicrystal Approximants to High Pressure Crystal Chemistry

Building a comprehensive solid state chemical toolbox that pairs experimental studies and computational modeling has proven particularly effective for the systematic exploration of metal rich inorganic solids. Here, we explored the complex crystal chemistry enabled by incorporating Au in the presence of electropositive (rare earth and alkali metals) and main group element systems revealing a series of compounds including Zintl-like structures, Frank-Kasper phases, interstitial Mn5Si3-type structures, classical Laves phases, and a decagonal quasicrystal approximant. Their formation and bonding is understood through comprehensive analysis of their electronic structure using density functional theory. Similarly, it is possible to add further complexity by applying external pressure, opening up the door to enormous potential for materials discovery. Yet, these experiments remain complex and uncommon. The challenges associated with high pressure synthesis have led to the development of computational-based crystal structure prediction algorithms to understand the complex crystal chemistry of inorganic solids at non ambient conditions. Using an unbiased automatic crystal structure searching method revealed that by applying pressure results in the identification of new phases in the Cs–Pt and Ca–Au system. Additionally, first-principle calculations can also be used to understand physical properties such as pressure-induced superconductivity in the Weyl semimetal (Mo0.5W0.5)Te2. These results support the formation of complex crystal structures enabled by Au, pressure-stabilized platinide phases and the presence of superconductivity in (Mo0.5W0.5)Te2 at high-pressure. Highlighting the use of computational models paired with experimental studies are key to understanding the chemistry dictating crystal structure formation and the ensuing properties for the development of next generation materials.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Houston

Year dc:date.issued

2024

Author dc:creator

• Arrieta, Roy Apolinar

Advisor dc:contributor.advisor

• Brgoch, Jakoah

Committee members dc:contributor.committeemember

• Teets, Thomas S
• Guloy, Arnold M
• Grabow, Lars C
• Xu, Shoujun

• Solid-state chemistry, intermetallics, computational chemistry, crystallography, materials discovery, high pressure chemistry

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10657/17750

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/17750