Hydrogen in layered iron arsenides: Indirect electron doping to induce superconductivity

Hanna, Taku; Muraba, Yoshinori; Matsuishi, Satoru; Igawa, Naoki; Kodama, Kazuhisa; Shamoto, S.; Hosono, Hideo

doi:10.1103/physrevb.84.024521

Cited by 118 publications

(178 citation statements)

References 56 publications

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“…As reported previously, LaFeAsO 1 − x H x was synthesized by solid-state reactions using starting materials La 2 O 3 , LaAs, LaH 2 , FeAs and Fe 2 As under high pressure 11 . The phase purity and structural parameters at room temperature were determined by powder X-ray diffraction measurements with MoKα1 radiation.…”

Section: Methodsmentioning

confidence: 94%

Two-dome structure in electron-doped iron arsenide superconductors

et al. 2012

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Iron arsenide superconductors based on the material LaFeAsO1-xFx are characterized by a two-dimensional Fermi surface (FS) consisting of hole and electron pockets yielding structural and antiferromagnetic transitions at x = 0. Electron doping by substituting O2- with F- suppresses these transitions and gives rise to superconductivity with a maximum Tc = 26 K at x = 0.1. However, the over-doped region cannot be accessed due to the poor solubility of F- above x = 0.2. Here we overcome this problem by doping LaFeAsO with hydrogen. We report the phase diagram of LaFeAsO1-xHx (x < 0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO1-xFx, we find a second dome in the range 0.21 < x < 0.53, with a maximum Tc of 36 K at x = 0.3. Density functional theory calculations reveal that the three Fe 3d bands (xy, yz, zx) become degenerate at x = 0.36, whereas the FS nesting is weakened monotonically with x. These results imply that the band degeneracy has an important role to induce high Tc.Comment: 31 pages, 4 figures, 1 table and supplementary informatio

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Section: Methodsmentioning

confidence: 94%

Two-dome structure in electron-doped iron arsenide superconductors

et al. 2012

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“…The rare earth (RE)FeAsO phases are AFM metals at low temperature. The electron doping via hydride ion substitution into the oxygen site results in the suppression of AFM (AFM1) ordering and subsequently the emergence of a superconducting phase for the electron doping range of 0.05 ≤ e − /Fe ≤ 0.45 (11,12). The optimum T c , which depends strikingly on the RE size, is 36 K for RE = La, and 56 K for Sm or Gd, consistent with the observation that the application of physical pressure to La-1111 can enhance its T c from 36 K to 52 K (12,13).…”

mentioning

confidence: 99%

Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x

Iimura

Okanishi

Matsuishi

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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In iron-based superconductors, high critical temperature (T c ) superconductivity over 50 K has only been accomplished in electron-doped hREFeAsO (hRE is heavy rare earth (RE) element). Although hREFeAsO has the highest bulk T c (58 K), progress in understanding its physical properties has been relatively slow due to difficulties in achieving high-concentration electron doping and carrying out neutron experiments. Here, we present a systematic neutron powder diffraction study of 154 SmFeAsO 1−x D x , and the discovery of a long-range antiferromagnetic ordering with x ≥ 0.56 (AFM2) accompanying a structural transition from tetragonal to orthorhombic. Surprisingly, the Fe magnetic moment in AFM2 reaches a magnitude of 2.73 μ B /Fe, which is the largest in all nondoped iron pnictides and chalcogenides. Theoretical calculations suggest that the AFM2 phase originates in kinetic frustration of the Fe-3d xy orbital, in which the nearest-neighbor hopping parameter becomes zero. The unique phase diagram, i.e., highest-T c superconducting phase adjacent to the strongly correlated phase in electron-overdoped regime, yields important clues to the unconventional origins of superconductivity.high-T c superconductivity | neutron scattering | oxyhydrides | iron-based superconductors | antiferromagnetism C arrier doping is a critical parameter that governs the electronic correlations and ground states in high-T c superconductors. Electronic phase diagrams depicting the evolution of the ground state with doping level not only deepen our understanding of the mechanism of superconductivity but help us extract common trends across different superconducting materials. Until recently, two electronic phases were believed to play a vital role in iron-based superconductivity, i.e., a stripe or double-stripe-type antiferromagnetic (AFM) ordering at a nondoped Fe-3d 6 state and a Mott insulator at a hole-doped Fe-3d 5 state (1-3). The former phase is observed at ambient pressure for the arsenides and telluride, while under high pressures for the selenides, and the AFM fluctuations are a promising candidate for the pairing glue leading to superconductivity (4, 5). On the other hand, the latter picture, confirmed recently in effectively hole-doped Na(Fe 3+ 0.5 Cu + 0.5 )As (6), explains the asymmetric response of the T c and electron correlation to hole and electron doping, where the hole doping (electron doping) into the Fe-3d 6 state tends to enhance (reduce) the T c and the degree of electron correlation, because the system approaches (goes away from) the half-filled Fe-3d 5 state (2).However, these two prevailing scenarios were challenged recently by observations of the behavior of heavily electron-doped FeSe (11-type) and REFeAsO (1111-type), where the T c and electron correlation strength are enhanced rather than weakened with electron doping. In the first of these systems, a quite high T c in the range of 35 K to 41 K was observed, for the electron-doped FeSe using an electric double-layer transistor, which climbs to 46 K to 48 K for ...

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“…A similar finding has been reported for undoped Ba/Sr122 single crystals, 86,87) in which the strain generated during crystal growth induces the superconductivity. Subsequently, it was reported that water-related species induce superconductivity in bulk samples of 1111 88,89) and 11 compounds [90][91][92] (as discussed later, there have been a few reports on 11 thin films). Thus, elucidating the interaction of water-related chemical species with the parent compounds could provide insight into the superconducting mechanism or a clue to realizing a higher T c by new doping methods such as chemical modification.…”

Section: Sr Systemmentioning

confidence: 96%

“…Note that Hanna et al 89) recently reported that hydrogen can be incorporated as H À anions and occupy the O 2À sites in the 1111 phase. The resulting SmFeAsO 1Àx H x (x ' 0:2) is a superconductor with T onset c ' 55 K. Additionally, up to 40% of the O 2À ions can be replaced by H À anions, along with electrons being supplied into the FeAs layer to maintain the charge neutrality (…”

Section: Sr Systemmentioning

confidence: 99%

Thin Film Growth and Device Fabrication of Iron-Based Superconductors

et al. 2012

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Iron-based superconductors have received much attention as a new family of high-temperature superconductors owing to their unique properties and distinct differences from cuprates and conventional superconductors. This paper reviews progress in thin film research on iron-based superconductors since their discovery for each of five material systems with an emphasis on growth, physical properties, device fabrication, and relevant bulk material properties.

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Hydrogen in layered iron arsenides: Indirect electron doping to induce superconductivity

Cited by 118 publications

References 56 publications

Two-dome structure in electron-doped iron arsenide superconductors

Two-dome structure in electron-doped iron arsenide superconductors

Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x

Thin Film Growth and Device Fabrication of Iron-Based Superconductors

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Hydrogen in layered iron arsenides: Indirect electron doping to induce superconductivity

Cited by 118 publications

References 56 publications

Two-dome structure in electron-doped iron arsenide superconductors

Two-dome structure in electron-doped iron arsenide superconductors

Large-moment antiferromagnetic order in overdoped high- T c superconductor 154 SmFeAsO 1− x D x

Thin Film Growth and Device Fabrication of Iron-Based Superconductors

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Product

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Large-moment antiferromagnetic order in overdoped high- T _c superconductor ¹⁵⁴ SmFeAsO _{1−
x} D _x