Implications of Vorticity and Disorder on Quantum Transport in Topological Semimetals

The study of quantum materials with topologically nontrivial band structures has revealed a wide range of unconventional responses to external perturbations. In this dissertation, we explore two distinct but conceptually related themes within the broad domain of topological and disordered condensed matter systems. In the first part, we investigate vortical and converse vortical effects in Weyl semimetals that break inversion symmetry. Using semiclassical and quantum kinetic frameworks, we analyze how Berry curvature and orbital magnetic moments generate charge and current responses in the presence of rotation and vorticity. The interplay between chirality, tilt, and Berry curvature leads to a family of vortical effects that mirror well-known chiral magnetic and chiral vortical responses, but with richer tensorial structures. We further establish reciprocity relations between vortical and converse vortical effects, clarifying their thermodynamic origin and symmetry constraints. In the second part, we turn to the problem of localization in disordered Dirac semimetals. Employing large-scale numerical simulations on high-performance computing clusters, we study the scaling of the Thouless conductance and Kubo conductivity in the presence of scalar and vector disorder. The results reveal distinct localization–delocalization behavior depending on the type of disorder and the tilt of the Dirac cone. In particular, we identify signatures of criticality near the transition between type-I and type-II Dirac phases, including changes in the scaling curvature and spectral properties. Together, these studies contribute to a unified understanding of how topology, symmetry, and disorder shape transport and response phenomena in gapless quantum systems. The findings offer both conceptual insight and quantitative benchmarks for future experimental and theoretical work on topological semimetals and related materials.

Name thesis:degree_name

Doctor of Philosophy

Discipline thesis:degree_discipline

Physics

Grantor

University of Houston

Year dc:date.issued

2025

Author dc:creator

• Nanda, Swadeepan 1997-

Advisor dc:contributor.advisor

• Hosur, Pavan

Committee members dc:contributor.committeemember

• Ratti, Claudia
• Bassler, Kevin E.
• Miller, John H.
• Sharma, Pradeep

• Transport properties
• Vortical effects
• Topological condensed matter
• Conductivity scaling
• Linear response
• Disordered systems

Language dc:language.iso

English

Handle dc:identifier.uri

https://hdl.handle.net/10657/20961

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/20961