Magnetic and pairing properties of a two-orbital model for the pnictide superconductors: a quantum Monte Carlo study

Liu, Guangkun; Huang, Zhegang; Wang, Yongjun

doi:10.1088/0953-8984/26/32/325601

Cited by 8 publications

(29 citation statements)

References 36 publications

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“…We studied the full and simplified models numerically by using three powerful techniques: DMRG [34][35][36], DQMC [37,38], and CPQMC [39][40][41][42][43]. Each of these techniques has its strengths and weaknesses.…”

Section: A Computational Techniquesmentioning

confidence: 99%

Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques

Liu

Kaushal

et al. 2016

Phys. Rev. E

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A recently introduced one-dimensional three-orbital Hubbard model displays orbital-selective Mott phases with exotic spin arrangements such as spin block states [J. Rincón et al., Phys. Rev. Lett. 112, 106405 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.106405]. In this publication we show that the constrained-path quantum Monte Carlo (CPQMC) technique can accurately reproduce the phase diagram of this multiorbital one-dimensional model, paving the way to future CPQMC studies in systems with more challenging geometries, such as ladders and planes. The success of this approach relies on using the Hartree-Fock technique to prepare the trial states needed in CPQMC. We also study a simplified version of the model where the pair-hopping term is neglected and the Hund coupling is restricted to its Ising component. The corresponding phase diagrams are shown to be only mildly affected by the absence of these technically difficult-to-implement terms. This is confirmed by additional density matrix renormalization group and determinant quantum Monte Carlo calculations carried out for the same simplified model, with the latter displaying only mild fermion sign problems. We conclude that these methods are able to capture quantitatively the rich physics of the several orbital-selective Mott phases (OSMP) displayed by this model, thus enabling computational studies of the OSMP regime in higher dimensions, beyond static or dynamic mean-field approximations.

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Section: A Computational Techniquesmentioning

confidence: 99%

Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques

Liu

Kaushal

et al. 2016

Phys. Rev. E

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“…We study the pairing correlation function by using CPQMC method, which is a sign-problem-free auxiliary-field quantum Monte Carlo method and projects out the ground state from a trial state by branching random walkers in the Slater determinant space. A constrained-path approximation is adoped to prevent the sign problem [48,49,50,51,52,53]. In our simulations, we set the average number of random walkers to be 6000 and the time step ∆τ = 0.04.…”

Section: Model and Methodsmentioning

confidence: 99%

“…In this paper, we studied the electron pairings on the AA-stacked bilayer graphene system. By using constrained-path quantum Monte Carlo method (CPQMC) [48,49,50,51,52,53], we systematically studied the impact of electric field on the AA-stacked bilayer graphene and our simulation results demonstrate a dominant chiral d + id-wave pairing triggered by the electric field. We find that such a dominance of chiral d + idwave pairing comes from the significantly increased density of states near Ferimi level and also enhanced antiferromagnetic fluctuations by the electric field.…”

Section: Introductionmentioning

confidence: 99%

Electric field-induced chiral d+id superconducting state in AA-stacked bilayer graphene: A quantum Monte Carlo study

Fang¹,

Zhang²,

Zheng³

et al. 2019

Preprint

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Using constrained-path quantum Monte Carlo method, we systematically study the Hubbard model on AA-stacked honeycomb lattices with electric field. Our simulation demonstrates a dominant chiral d + id wave pairing induced by the electric field at half filling. In particular, as the on-site Coulomb interaction increases, the effective pairing correlation of chiral d + id superconducting state exhibits increasing behavior. We attribute the electric field induced d + id superconductivity to an increased density of states near the Fermi energy and an suppressed antiferromagnetic spin correlation after turning on the electric field. Our results strongly suggest the AA-stacked graphene system with electric field is a good candidate for chiral d + id superconductors.

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“…The two-orbital model was also shown to be suitable to describe the extended s-wave pairing believed to be relevant for ferropnictides, and other details of the superconducting phase. [31][32][33][34][35][36][37]66 In this work, we will study the doping and temperature effects on the electronic structure and spectral properties, using the following microscopic model for the normal state of pnictides:…”

Section: Microscopic Model and Analytical Approachmentioning

confidence: 99%

Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides

et al. 2016

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Using a second-order perturbative Green's functions approach we determined the normal state spectral function A( k, ω) employing a minimal model for ferropnictides. Used before to study magnetic fluctuations and superconducting properties, it includes the two effective bands related to Fe-3d orbitals proposed by S. Raghu et al. [Phys. Rev. B 77, 220503 (R) (2008)], and local intra-and inter-orbital correlations for the effective orbitals. Here, we focus on the normal state electronic properties, in particular the temperature and doping dependence of the total density of states, A(ω), and of A( k, ω) in different Brillouin zone regions, comparing them with existing angle resolved photoemission spectroscopy (ARPES) and theoretical results. We obtain an asymmetric effect of electron and hole doping, quantitative agreement with the experimental chemical potential shifts, as well as spectral weight redistributions near the Fermi level with temperature consistent with the available experiments. In addition, we predict a non-trivial dependence of A(ω) with temperature, exhibiting clear renormalization effects by correlations. Interestingly, investigating the origin of this predicted behaviour by analyzing the evolution with temperature of the k-dependent self-energy obtained in our approach, we could identify a number of Brillouin zone points, not probed by ARPES yet, where the largest non-trivial effects of temperature on the renormalization are predicted for the parent compounds.

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Magnetic and pairing properties of a two-orbital model for the pnictide superconductors: a quantum Monte Carlo study

Cited by 8 publications

References 36 publications

Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques

Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques

Electric field-induced chiral d+id superconducting state in AA-stacked bilayer graphene: A quantum Monte Carlo study

Temperature and doping dependence of normal state spectral properties in a two-orbital model for ferropnictides

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