First, I introduce the concept of heavy fermion systems and discuss the ease of tuning their properties with external parameters including pressure, chemical doping, and magnetic fields to induce new quantum states such as unconventional superconductivity. I then delve into the limited use of dimensionality as a tuning knob for quantum criticality and highlight the new possibilities available if heavy fermion behavior is discovered in the single-layer limit.
Chapter 1 establishes the van der Waals material, CeSiI, as a heavy fermion system and is the first material where heavy fermion behavior exists down to the few-layer limit. The chapter further explores the bulk magnetic properties and electronic structure of CeSiI at high magnetic fields. The quasi-two-dimensional electronic character of CeSiI leads to anisotropic hybridization between local moments and conduction electrons, a phenomenon previously only realized in theoretical calculations.
With the heavy fermion properties of CeSiI established, Chapter 2 investigates the effects of pressure and La-doping on CeSiI, aiming to push it from the antiferromagnetic region of the Doniach phase diagram towards a quantum critical point. Preliminary evidence suggests that CeSiI is too distant from quantum criticality. Instead, La-doping is utilized to explore single-ion Kondo physics at the dilute Ce limit in CeSiI. Additionally, CeGaI, with a crystal structure similar to CeSiI, is examined. Although no Kondo physics is observed, the magnetic and electronic properties remain coupled to each other.
Chapter 3 delves into a separate project focusing on the study of polymers composed of perylene diimide and various organic linkers. It explores how the structure of the polymer influences its pseudocapacitance properties. The chapter demonstrates the significance of contortion in device performance, aiming to provide insights for future endeavors in developing environmentally friendly energy storage systems.
| Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/07x8-p749 |
| Date | January 2024 |
| Creators | Posey, Victoria |
| Source Sets | Columbia University |
| Language | English |
| Detected Language | English |
| Type | Theses |
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