We investigate a semimetal-superconductor phase transition of two-dimensional Dirac electrons at zero temperature by large-scale and essentially unbiased quantum Monte Carlo simulations for the half-filled attractive Hubbard model on the triangular lattice, in the presence of alternating magnetic π flux, that is introduced to construct two Dirac points in the one-particle bands at the Fermi level. This phase transition is expected to describe quantum criticality of the chiral XY class in the framework of the Gross-Neveu model, where, in the ordered phase, the U(1) symmetry is spontaneously broken and a mass gap opens in the excitation spectrum. We compute the order parameter of the s-wave superconductivity and estimate the quasiparticle weight from the long-distance behavior of the single-particle Green's function. These calculations allow us to obtain the critical exponents of this transition in a reliable and accurate way. Our estimate for the critical exponents is in good agreement with those obtained for a transition to a Kekulé valence bond solid, where an emergent U(1) symmetry is proposed [Z.-X. Li, Nat. Commun. 8, 314 (2017)2041-172310.1038/s41467-017-00167-6].

Quantum criticality in the metal-superconductor transition of interacting Dirac fermions on a triangular lattice / Otsuka, Yuichi; Seki, Kazuhiro; Sorella, Sandro; Yunoki, Seiji. - In: PHYSICAL REVIEW. B. - ISSN 2469-9950. - 98:3(2018), pp. 1-8. [10.1103/PhysRevB.98.035126]

Quantum criticality in the metal-superconductor transition of interacting Dirac fermions on a triangular lattice

Otsuka, Yuichi
Membro del Collaboration group
;
Seki, Kazuhiro
Membro del Collaboration group
;
Sorella, Sandro
Membro del Collaboration group
;
Yunoki, Seiji
Membro del Collaboration group
2018

Abstract

We investigate a semimetal-superconductor phase transition of two-dimensional Dirac electrons at zero temperature by large-scale and essentially unbiased quantum Monte Carlo simulations for the half-filled attractive Hubbard model on the triangular lattice, in the presence of alternating magnetic π flux, that is introduced to construct two Dirac points in the one-particle bands at the Fermi level. This phase transition is expected to describe quantum criticality of the chiral XY class in the framework of the Gross-Neveu model, where, in the ordered phase, the U(1) symmetry is spontaneously broken and a mass gap opens in the excitation spectrum. We compute the order parameter of the s-wave superconductivity and estimate the quasiparticle weight from the long-distance behavior of the single-particle Green's function. These calculations allow us to obtain the critical exponents of this transition in a reliable and accurate way. Our estimate for the critical exponents is in good agreement with those obtained for a transition to a Kekulé valence bond solid, where an emergent U(1) symmetry is proposed [Z.-X. Li, Nat. Commun. 8, 314 (2017)2041-172310.1038/s41467-017-00167-6].
98
3
1
8
035126
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.98.035126
https://arxiv.org/abs/1803.02001
Otsuka, Yuichi; Seki, Kazuhiro; Sorella, Sandro; Yunoki, Seiji
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/87955
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