Band renormalization and Fermi surface reconstruction in iron-based superconductors

Yu, Shun-Li; Kang, Jing; Li, Jianxin

doi:10.1103/physrevb.79.064517

Cited by 53 publications

(48 citation statements)

References 42 publications

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“…86 We note that there are several alternative three-orbital models which display an xy-dominated hole pocket at the M point. 44,53 A similar analysis to that performed here has been carried out for such a three-orbital model, 62 and the susceptibility was found to be peaked at an incommensurate wavevector close to (π, 0). More recently, Zhou and Wang studied a three-orbital model of LaFeAsO using Gutzwiller mean-field theory restricted to two-site magnetic unit cells and found significant deviations from the usual Hartree-Fock approach.…”

Section: Resultssupporting

confidence: 72%

“…81 Although the existence of superconductivity in these models has been extensively studied, 40,[44][45][46]48,51,53,56,60,63,64,66 the magnetic behaviour remains rather poorly understood. The most popular approach to the appearance of AFM order in these models is to examine the ground state using a standard mean-field ansatz that allows for at most twosite magnetic unit cells; 47,50,52,54,58,59,61,64 very recently, this has been generalized to a Gutzwiller mean-field theory.…”

Section: Arxiv:10071949v2 [Cond-matsupr-con] 27 May 2011mentioning

confidence: 99%

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Magnetic order in orbital models of the iron pnictides

Brydon¹,

Daghofer²,

Timm³

2011

J. Phys.: Condens. Matter

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We examine the appearance of the experimentally-observed stripe spin-density-wave magnetic order in five different orbital models of the iron pnictide parent compounds. A restricted meanfield ansatz is used to determine the magnetic phase diagram of each model. Using the random phase approximation, we then check this phase diagram by evaluating the static spin susceptibility in the paramagnetic state close to the mean-field phase boundaries. The momenta for which the susceptibility is peaked indicate in an unbiased way the actual ordering vector of the nearby meanfield state. The dominant orbitally resolved contributions to the spin susceptibility are also examined to determine the origin of the magnetic instability. We find that the observed stripe magnetic order is possible in four of the models, but it is extremely sensitive to the degree of the nesting between the electron and hole Fermi pockets. In the more realistic five-orbital models, this order competes with a strong-coupling incommensurate state which appears to be controlled by details of the electronic structure below the Fermi energy. We conclude by discussing the implications of our work for the origin of the magnetic order in the pnictides.

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Section: Resultssupporting

confidence: 72%

Section: Arxiv:10071949v2 [Cond-matsupr-con] 27 May 2011mentioning

confidence: 99%

Magnetic order in orbital models of the iron pnictides

Brydon¹,

Daghofer²,

Timm³

2011

J. Phys.: Condens. Matter

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“…At this electronic density, the Fermi surface is in agreement with experiments. Previously proposed three-orbital models [50,75] only contained the NN hybridization t 7 , but since NNN terms are included for the intra-orbital component, as well as for the hybridization between xz and yz, they should also be included in the hybridization with xy. It can be shown that these NNN terms with hopping t 8 turn out to be very important to provide the proper orbital character for the electron pockets when compared with LDA results.…”

Section: Real Spacementioning

confidence: 99%

Properties of the multiorbital Hubbard models for the iron-based superconductors

et al. 2011

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A brief review of the main properties of multiorbital Hubbard models for the Fe-based superconductors is presented. The emphasis is on the results obtained by our group at the University of Tennessee and Oak Ridge National Laboratory, Tennessee, USA, but results by several other groups are also discussed. The models studied here have two, three, and five orbitals, and they are analyzed using a variety of computational and mean-field approximations. A "physical region" where the properties of the models are in qualitative agreement with neutron scattering, photoemission, and transport results is revealed. A variety of interesting open questions are briefly discussed such as: what are the dominant pairing tendencies in Hubbard models? Can pairing occur in an interorbital channel? Are nesting effects of fundamental relevance in the pnictides or approaches based on local moments are more important? What kind of magnetic states are found in the presence of iron vacancies? Can charge stripes exist in iron-based superconductors? Why is transport in the pnictides anisotropic? The discussion of results includes the description of these and other open problems in this fascinating area of research.

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“…A study based on the similar consideration for the interactions in the two-orbital model for pnictide superconductors with both electron and hole FS has been carried out from the strong coupling expansion 34 . We carry out the investigation using the FLEX approximation [35][36][37] , in which the Green's function and the spin/charge fluctuations are determined selfconsistently. Here, we consider the following spin fluctuationsχ s (q, iω n ) and charge fluctuationsχ c (q, iω n ):…”

Section: Model and Flex Methodsmentioning

confidence: 99%

Spin fluctuations and pairing symmetry in A_xFe_2−ySe₂: dual effect of the itinerant and the localized nature of electrons

Yu¹,

Guo²,

Li³

2013

J. Phys.: Condens. Matter

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We investigate the spin fluctuations and the pairing symmetry in AxFe2−ySe2 by the fluctuation exchange approximation. Besides the on-site interactions, the next-nearest-neighbor antiferromagnetic coupling J2 is also included. We find that both the itinerant and the localized natures of electrons are important to describe the recent experimental results of the spin fluctuations and the pairing symmetry. In particular, a small J2 coupling can change the pairing gap from the dwave symmetry to the s-wave symmetry. We have also studied the real-space structures of the gap functions for different orbits in order to gain more insight on the nature of the pairing mechanism.

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Band renormalization and Fermi surface reconstruction in iron-based superconductors

Cited by 53 publications

References 42 publications

Magnetic order in orbital models of the iron pnictides

Magnetic order in orbital models of the iron pnictides

Properties of the multiorbital Hubbard models for the iron-based superconductors

Spin fluctuations and pairing symmetry in A_xFe_2−ySe₂: dual effect of the itinerant and the localized nature of electrons

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Band renormalization and Fermi surface reconstruction in iron-based superconductors

Cited by 53 publications

References 42 publications

Magnetic order in orbital models of the iron pnictides

Magnetic order in orbital models of the iron pnictides

Properties of the multiorbital Hubbard models for the iron-based superconductors

Spin fluctuations and pairing symmetry in AxFe2−ySe2: dual effect of the itinerant and the localized nature of electrons

Contact Info

Product

Resources

About

Spin fluctuations and pairing symmetry in A_xFe_2−ySe₂: dual effect of the itinerant and the localized nature of electrons