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arXiv · 1802.00364

Fermion-induced quantum criticality with two length scales in Dirac systems

Emilio Torres·Laura Classen·Igor F. Herbut·Michael M. Scherer
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Abstract

The quantum phase transition to a $\mathbb{Z}_3$-ordered Kekulé valence bond solid in two-dimensional Dirac semimetals is governed by a fermion-induced quantum critical point, which renders the putatively discontinuous transition continuous. We study the resulting universal critical behavior in terms of a functional RG approach, which gives access to the scaling behavior on the symmetry-broken side of the phase transition, for general dimension and number of Dirac fermions. In particular, we investigate the emergence of the fermion-induced quantum critical point for space-time dimensions $2<d<4$. We determine the integrated RG flow from the Dirac semi-metal to the symmetry-broken regime and analyze the underlying fixed point structure. We show that the fermion-induced criticality leads to a scaling form with two divergent length scales, due to the breaking of the discrete $\mathbb{Z}_3$ symmetry. This provides another source of scaling corrections, besides the one stemming from being in the proximity to the first order transition.

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Emilio Torres, Laura Classen, Igor F. Herbut, Michael M. Scherer. 2018-02-01. Fermion-induced quantum criticality with two length scales in Dirac systems. https://doi.org/10.1103/physrevb.97.125137

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