Research: Dirac cones on the tramp

Topological semimetals are electronic systems that feature protected band crossings at isolated points in the Brillouin zone, such as Weyl or Dirac cones. In many cases, the locations of these band crossing points are fixed by symmetry.

Research performed within SFB 1143 in collaboration with the Julius-Maximilians-Universität of Würzburg has now identified an example of a strongly-correlated Dirac system in which the symmetry that fixes the positions of the Dirac cones becomes spontaneously broken at low temperatures. This induces a meandering of the Dirac cones within the Brillouin zone. Using large-scale quantum Monte Carlo simulations and a concomitant field-theoretical analysis, the corresponding quantum phase transition has been identified as a novel quantum critical point.

These results may be of importance for the understanding of d-wave high-temperature superconductors and other strongly-correlated systems.

J. Schwab, L. Janssen, K. Sun, Z. Y. Meng, I. F. Herbut, M. Vojta, F. F. Assaad,
Nematic Quantum Criticality in Dirac Systems,
Phys. Rev. Lett. 128, 157203 (2022)