Phase transition with trivial quantum criticality in anisotropic Weyl semimetal.
When a metal undergoes continuous quantum phase transition, the correlation length diverges at the critical point and the quantum fluctuation of order parameter is described by a gapless bosonic mode. In most cases, this bosonic mode induces a variety of unusual quantum critical phenomena, including non-Fermi liquid behavior and various emergent symmetries. Here, we perform a renormalization group analysis of the semimetal-superconductor quantum criticality in a three-dimensional anisotropic Weyl semimetal, in which the fermion dispersion is linear in two of the momentum components and quadratical in the third. Unexpectedly, distinct from previously studied quantum critical systems, the Weyl fermions do not acquire an anomalous dimension at the critical point, and their quasiparticle residue takes a nonzero value. This indicates that the fermions can be well described by the model of non-interacting fermion gas even at the quantum critical point. We thus obtain a phase transition that exhibits trivial quantum criticality, which is unique comparing to other invariably nontrivial quantum critical systems.
Publisher URL: http://arxiv.org/abs/1801.05631