Yoshinori Muraba

Two-dome structure in electron-doped iron arsenide superconductors

Iron arsenide superconductors based on the material LaFeAsO(1-x)F(x) 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 O(2-) with F(-) suppresses these transitions and gives rise to superconductivity with a maximum T(c) of 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 LaFeAsO(1-x)H(x) (x<0.53) and, in addition to the conventional superconducting dome seen in LaFeAsO(1-x)F(x), we find a second dome in the range 0.21<x<0.53, with a maximum T(c) of 36 K at x=0.3. Density functional theory calculations reveal that the three Fe 3d bands (xy, yz and 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 T(c).

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

Utilizing the high stability of calcium and rare-earth hydrides, CaFeAsF

Discovery of earth-abundant nitride semiconductors by computational screening and high-pressure synthesis.

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Superconductivity at 52 K in hydrogen-substituted LaFeAsO1-xHx under high pressure

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La-Substituted CaFeAsH Superconductor with Tc = 47 K

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Enhancing the three-dimensional electronic structure in 1111-type iron arsenide superconductors by H substitution

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Hydrogen-Substituted Superconductors SmFeAsO1–xHx Misidentified As Oxygen-Deficient SmFeAsO1–x

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Superconductivity in 1111-type CaFeAsF1−xHx induced by selective hydrogen elimination

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High-pressure studies for hydrogen substituted CaFeAsF1−xHx

0.0\char21{}1.0) and SmFeAsO