Competition of density waves and quantum multicritical behavior in Dirac materials from functional renormalization

• Verfasst von: Classen, Laura [VerfasserIn]
• Verfasst von: Herbut, Igor F. [VerfasserIn]
• Verfasst von: Janssen, Lukas [VerfasserIn]
• Verfasst von: Scherer, Michael [VerfasserIn]
• Titel: Competition of density waves and quantum multicritical behavior in Dirac materials from functional renormalization
• Verf.angabe: Laura Classen, Igor F. Herbut, Lukas Janssen, and Michael M. Scherer
• Jahr: 2016
• Jahr des Originals: 2015
• Fussnoten: Online erschienen: 30 October 2015 ; Gesehen am 04.05.2020
• Titel Quelle: Enthalten in: Physical review
• Ort Quelle: Woodbury, NY : Inst., 2016
• Jahr Quelle: 2016
• Band/Heft Quelle: 93(2016) Artikel-Nummer 125119, 20 Seiten
• ISSN Quelle: 2469-9969
• DOI: doi:10.1103/PhysRevB.93.125119
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1697018122

Abstract

We study the competition of spin- and charge-density waves and their quantum multicritical behavior for the semimetal-insulator transitions of low-dimensional Dirac fermions. Employing the effective Gross-Neveu-Yukawa theory with two order parameters as a model for graphene and a growing number of other two-dimensional Dirac materials allows us to describe the physics near the multicritical point at which the semimetallic and the spin- and charge-density-wave phases meet. With the help of a functional renormalization group approach, we are able to reveal a complex structure of fixed points, the stability properties of which decisively depend on the number of Dirac fermions Nf. We give estimates for the critical exponents and observe crucial quantitative corrections as compared to the previous first-order ε expansion. For small Nf, the universal behavior near the multicritical point is determined by the chiral Heisenberg universality class supplemented by a decoupled, purely bosonic, Ising sector. At large Nf, a novel fixed point with nontrivial couplings between all sectors becomes stable. At intermediate Nf, including the graphene case (Nf=2), no stable and physically admissible fixed point exists. Graphene's phase diagram in the vicinity of the intersection between the semimetal, antiferromagnetic, and staggered density phases should consequently be governed by a triple point exhibiting first-order transitions.