Pressure effects on the electronic properties of the undoped superconductor ThFeAsN

Article

关键词: HIGH-TEMPERATURE SUPERCONDUCTIVITY;    TOTAL-ENERGY CALCULATIONS;   

DOI  :  10.1103/PhysRevB.97.140506

来源: SCIE

【 摘 要 】

The recently synthesized ThFeAsN iron pnictide superconductor exhibits a T-c of 30 K, the highest of the 1111-type series in the absence of chemical doping. To understand how pressure affects its electronic properties, we carried out microscopic investigations up to 3 GPa via magnetization, nuclear magnetic resonance, and muon-spin rotation experiments. The temperature dependence of the As-75 Knight shift, the spin-lattice relaxation rates, and the magnetic penetration depth suggest a multiband s(+/-)-wave gap symmetry in the dirty limit, whereas the gap-to-T-c ratio Delta/k(B)T(c) hints at a strong-coupling scenario. Pressure modulates the geometrical parameters, thus reducing T-c as well as T-m, the temperature where magnetic-relaxation rates are maximized, both at the same rate of approximately -1.1 K/GPa. This decrease in T-c with pressure is consistent with band-structure calculations, which relate it to the deformation of the Fe 3d(z2) orbitals.

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