Theory of a 3+1D fractional chiral metal: Interacting variant of the Weyl semimetal

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Tobias Meng - , Chair of Theoretical Solid State Physics (Author)
  • Adolfo G. Grushin - , University of California at Berkeley, Max-Planck-Institute for the Physics of Complex Systems (Author)
  • Kirill Shtengel - , Max-Planck-Institute for the Physics of Complex Systems, University of California at Riverside (Author)
  • Jens H. Bardarson - , Max-Planck-Institute for the Physics of Complex Systems (Author)

Abstract

Formulating consistent theories describing strongly correlated metallic topological phases is an outstanding problem in condensed-matter physics. In this work, we derive a theory defining a fractionalized analog of the Weyl semimetal state: the fractional chiral metal. Our approach is to construct a 4+1D quantum Hall insulator by stacking 3+1D Weyl semimetals in a magnetic field. In a strong enough field, the low-energy physics is determined by the lowest Landau level of each Weyl semimetal, which is highly degenerate and chiral, motivating us to use a coupled-wire approach. The one-dimensional dispersion of the lowest Landau level allows us to model the system as a set of degenerate 1+1D quantum wires that can be bosonized in the presence of electron-electron interactions and coupled such that a gapped phase is obtained whose response to an electromagnetic field is given in terms of a Chern-Simons field theory. At the boundary of this phase, we obtain the field theory of a 3+1D gapless fractional chiral state, which we show is consistent with a previous theory for the surface of a 4+1D Chern-Simons theory. The boundary's response to an external electromagnetic field is determined by a chiral anomaly with a fractionalized coefficient. We suggest that such an anomalous response can be taken as a working definition of a fractionalized strongly correlated analog of the Weyl semimetal state.

Details

Original languageEnglish
Article number155136
JournalPhysical Review B
Volume94
Issue number15
Publication statusPublished - 20 Oct 2016
Peer-reviewedYes