Electronic structure of Fe-based superconductors

Singh, David J.

doi:10.1016/j.physc.2009.03.035

Cited by 140 publications

(122 citation statements)

References 111 publications

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“…[17] This dip at an electron count of six per Fe does not correspond to a tetrahedral crystal field (in which the 4-fold e g manifold would be lower) but instead reflects metal-metal bonding in addition to the interaction of Fe with the As ligands, as was discussed previously for other Fe-based superconductors. [17,21] The value of the DOS at E F is N (E F )=2.02 eV −1 per formula unit and as seen in the projection is more than 80% from Fe d states. This places the compound at a Stoner instability.…”

Section: Resultsmentioning

confidence: 98%

ThFeAsN in relation to other iron-based superconductors

Singh

2016

Journal of Alloys and Compounds

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The electronic structure, magnetic and structural properties of the superconductor ThFeAsN are discussed in relation to the Fe-pnictide and Fe-chalcogenide superconductors based on results of first principles calculations. The electronic structure is that of a high density of states semimetal. It shows approximately nested hole and electron Fermi surfaces of Fe d character involving the xz, yz and xy orbitals. There is a strong tendency towards magnetism at the GGA level, and this magnetism is important for describing the Fe-As bonding, but greatly overestimates the magnetic ordering. The lowest energy magnetic state at the GGA level is the stripe order, and this particular order couples strongly to electrons near E F . ThFeAsN is therefore strongly similar to the Fe-pnictide family of superconductors, although it is a particularly anisotropic member.

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Section: Resultsmentioning

confidence: 98%

ThFeAsN in relation to other iron-based superconductors

Singh

2016

Journal of Alloys and Compounds

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“…Thus, the Fe atoms sit in the tetrahedral cavities of the tetragonally distorted close packed lattice of Se (or As). 43 We also note that the structure of PdTe places Pd atoms closer to each other than in a perovskite; as such, direct PdPd hybridization becomes important as we will discuss below.…”

Section: 41mentioning

confidence: 97%

First-principles Wannier function analysis of the electronic structure of PdTe: weaker magnetism and superconductivity

Ekuma¹,

Lin²,

Moreno³

et al. 2013

J. Phys.: Condens. Matter

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We report a first-principles Wannier function study of the electronic structure of PdTe. Its electronic structure is found to be a broad three-dimensional Fermi surface with highly reduced correlations effects. In addition, the higher filling of the Pd d-shell, its stronger covalency resulting from the closer energy of the Pd-d and Te-p shells, and the larger crystal field effects of the Pd ion due to its near octahedral coordination all serve to weaken significantly electronic correlations in the particle-hole (spin, charge, and orbital) channel. In comparison to the Fe Chalcogenide e.g., FeSe, we highlight the essential features (quasi-two-dimensionality, proximity to half-filling, weaker covalency, and higher orbital degeneracy) of Fe-based high-temperature superconductors.PACS numbers: 31.15. 74.70.Ad, 71.15.Ap, 71.27.+a

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“…Band-structure calculations [10] showed several Fe 3d orbital bands crossing the Fermi level, form cylinder-like Fermi surface sheets significantly warped in out-of-plane direction, hole-like around the Г point, and electron-like around the M point. The presence of multiple superconducting condensates below TC and corresponding forbidden energy bands (superconducting gaps) had unambiguous confirmation, both theoretical and experimental [11,12].…”

Section: Introductionmentioning

confidence: 99%

On the structure of the superconducting order parameter in high-temperature Fe-based superconductors

Kuzmicheva¹,

Muratov²,

Kuzmichev³

et al. 2017

Phys.-Usp.

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We discuss the synthesis, characterization, and comprehensive study of Ba-122 single crystals with various substitutions and various superconducting transition temperatures. We use five complementary techniques to obtain a self-consistent set of data on the superconducting properties of Ba-122. A major conclusion of our work is the coexistence of two superconducting condensates differing in the electron–boson coupling strength. The two gaps that develop in distinct Fermi surface sheets are nodeless in the kxky plane and exhibit s-wave symmetry; the two-band model suffices for the description of the main parameters of the superconducting state. A moderate interband coupling and a considerable Coulomb repulsion in the description of the two-gap superconducting state of barium pnictides favor the s++ model.

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Electronic structure of Fe-based superconductors

Cited by 140 publications

References 111 publications

ThFeAsN in relation to other iron-based superconductors

ThFeAsN in relation to other iron-based superconductors

First-principles Wannier function analysis of the electronic structure of PdTe: weaker magnetism and superconductivity

On the structure of the superconducting order parameter in high-temperature Fe-based superconductors

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