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

Abstract

The 1111-type iron-based superconductor LnFeAsO1-xFx (Ln stands for lanthanide) is the first material with a Tc above 50 K, other than cuprate superconductors. Electron doping into LaFeAsO by H, rather than F, revealed a double-dome-shaped Tc-x diagram, with a first dome (SC1, 0.05<x<0.20) and a second dome (SC2, 0.2<x<0.5). Here, we report the Tc for the whole hydrogen-doping range in LaFeAsO1-xHx under pressures of up to 19 GPa. Tc rises to 52 K at 6 GPa for the Tc-valley composition between the two Tc domes. This is the first instance of the Tc exceeding 50 K in La-1111-type iron-based superconductors. On the other hand, the Tc of SmFeAsO1-xHx decreased continually, keeping its single-dome structure up to 15 GPa. The present findings strongly suggest that the main reason for realization of the Tc >50 K observed in RE-1111 compounds (RE: Pr, Sm, and Gd) at ambient pressure is the merging of SC1 and SC2.

11 pages, 4 figures

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Cited by in corpus (7)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• A large moment antiferromagnetic order in overdoped high-Tc superconductor 154SmFeAsO1-xDx
• Heavily Hydride-ion-doped 1111-type Iron-based Superconductors: Synthesis, Physical Properties and Electronic Structure
• Experimental evidence of $T_c$ enhancement without the influence of spin fluctuations: NMR study on LaFeAsO_{1-x}H_x under a pressure of 3.0 GPa
• Quantum Phase transition under pressure in a heavily hydrogen-doped iron-based superconductor LaFeAsO
• Magnetism driven by strong electronic correlation in the heavily carrier-doped iron oxypnictide LaFeAsO${}_{0.49}$H${}_{0.51}$
• Observation of the bands with $d_{xy}$ orbital character near the Fermi level in NdFeAs${}_{1-x}$P${}_x$O${}_{0.9}$F${}_{0.1}$ using angle-resolved photoemission spectroscopy