Patterns of electro-magnetic response in topological semi-metals

Topological semimetals are gapless states of matter which have robust and unique electromagnetic responses and surface states. In this thesis, we consider semimetals which have point like Fermi surfaces in various spatial dimensions $D=1,2,3$ which naturally occur in the transition between $n$th order weak topological insulators and a trivial insulating phase. These semimetals include those of Dirac and Weyl type. We construct these phases by layering strong topological insulator phases in lower dimensions. This perspective helps us understand their effective response field theory, which is generally characterized by a $n$-form which represents a source of Lorentz violation and can be read off from the location of the singular points in momentum space and the helicities/chiralities of the singularities. We motivate and derive effective response actions for the 2D and 3D Dirac semi-metals, the Weyl semimetal, the 3D line node semi-metal and the 3D mirror protected topological crystalline insulator.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Ramamurthy, Srinidhi T.

Contributors dc:contributor

• Hughes, Taylor L.
• Phillips, Philip W.
• Cooper, S. Lance
• Leigh, Robert G.

• Topological physics, Topological semi-metals, Electromagnetic response.

Statement dc:rights

• Copyright 2019 Srinidhi Ramamurthy

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/104736

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/104736