Universität zu Köln

Classen, Laura, Herbut, Igor F. and Scherer, Michael M. ORCID: 0000-0003-0766-9949 (2017). Fluctuation-induced continuous transition and quantum criticality in Dirac semimetals. Phys. Rev. B, 96 (11). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We establish a scenario where fluctuations of new degrees of freedom at a quantum phase transition change the nature of a transition beyond the standard Landau-Ginzburg paradigm. To this end, we study the quantum phase transition of gapless Dirac fermions coupled to a Z(3) symmetric order parameter within a Gross-Neveu-Yukawa model in 2+1 dimensions, appropriate for the Kekule transition in honeycomb lattice materials. For this model, the standard Landau-Ginzburg approach suggests a first-order transition due to the symmetry-allowed cubic terms in the action. At zero temperature, however, quantum fluctuations of the massless Dirac fermions have to be included. We show that they reduce the putative first-order character of the transition and can even render it continuous, depending on the number of Dirac fermions N-f. A nonperturbative functional renormalization group approach is employed to investigate the phase transition for a wide range of fermion numbers and we obtain the critical N-f, where the nature of the transition changes. Furthermore, it is shown that for large N-f the change from the first to second order of the transition as a function of dimension occurs exactly in the physical 2+1 dimensions. We compute the critical exponents and predict sizable corrections to scaling for N-f = 2.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Classen, Laura UNSPECIFIED UNSPECIFIED UNSPECIFIED Herbut, Igor F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scherer, Michael M. UNSPECIFIED orcid.org/0000-0003-0766-9949 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-217536
DOI:	10.1103/PhysRevB.96.115132
Journal or Publication Title:	Phys. Rev. B
Volume:	96
Number:	11
Date:	2017
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CRITICAL EXPONENTS; PHASE-TRANSITIONS; POTTS-MODEL; RENORMALIZATION; FERMIONS; COLLOQUIUM; EQUATION Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/21753