Correlated topological insulators and the fractional magnetoelectric effect
Abstract
Topological insulators are characterized by the presence of gapless surface modes protected by timereversal symmetry. In three space dimensions the magnetoelectric response is described in terms of a bulk {theta} term for the electromagnetic field. Here we construct theoretical examples of such phases that cannot be smoothly connected to any band insulator. Such correlated topological insulators admit the possibility of fractional magnetoelectric response described by fractional {theta}/{pi}. We show that fractional {theta}/{pi} is only possible in a gapped timereversalinvariant system of bosons or fermions if the system also has deconfined fractional excitations and associated degenerate ground states on topologically nontrivial spaces. We illustrate this result with a concrete example of a timereversalsymmetric topological insulator of correlated bosons with {theta}=({pi}/4). Extensions to electronic fractional topological insulators are briefly described.
 Authors:

 Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
 Publication Date:
 OSTI Identifier:
 21544767
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review. B, Condensed Matter and Materials Physics
 Additional Journal Information:
 Journal Volume: 83; Journal Issue: 19; Other Information: DOI: 10.1103/PhysRevB.83.195139; (c) 2011 American Institute of Physics; Journal ID: ISSN 10980121
 Country of Publication:
 United States
 Language:
 English
 Subject:
 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOSONS; ELECTRICAL PROPERTIES; ELECTROMAGNETIC FIELDS; EXCITATION; FERMIONS; GROUND STATES; MAGNETIC FIELDS; MAGNETIC PROPERTIES; SIMULATION; SURFACES; SYMMETRY; TOPOLOGY; ENERGY LEVELS; ENERGYLEVEL TRANSITIONS; MATHEMATICS; PHYSICAL PROPERTIES
Citation Formats
Swingle, B, Barkeshli, M, McGreevy, J, and Senthil, T. Correlated topological insulators and the fractional magnetoelectric effect. United States: N. p., 2011.
Web. doi:10.1103/PHYSREVB.83.195139.
Swingle, B, Barkeshli, M, McGreevy, J, & Senthil, T. Correlated topological insulators and the fractional magnetoelectric effect. United States. doi:10.1103/PHYSREVB.83.195139.
Swingle, B, Barkeshli, M, McGreevy, J, and Senthil, T. Sun .
"Correlated topological insulators and the fractional magnetoelectric effect". United States. doi:10.1103/PHYSREVB.83.195139.
@article{osti_21544767,
title = {Correlated topological insulators and the fractional magnetoelectric effect},
author = {Swingle, B and Barkeshli, M and McGreevy, J and Senthil, T},
abstractNote = {Topological insulators are characterized by the presence of gapless surface modes protected by timereversal symmetry. In three space dimensions the magnetoelectric response is described in terms of a bulk {theta} term for the electromagnetic field. Here we construct theoretical examples of such phases that cannot be smoothly connected to any band insulator. Such correlated topological insulators admit the possibility of fractional magnetoelectric response described by fractional {theta}/{pi}. We show that fractional {theta}/{pi} is only possible in a gapped timereversalinvariant system of bosons or fermions if the system also has deconfined fractional excitations and associated degenerate ground states on topologically nontrivial spaces. We illustrate this result with a concrete example of a timereversalsymmetric topological insulator of correlated bosons with {theta}=({pi}/4). Extensions to electronic fractional topological insulators are briefly described.},
doi = {10.1103/PHYSREVB.83.195139},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {10980121},
number = 19,
volume = 83,
place = {United States},
year = {2011},
month = {5}
}