Superfluid density and superconducting gaps of RbFe₂As₂ as a function of hydrostatic pressure

الأصل · EN

The superfluid density and superconducting gaps of superconducting RbFe₂As₂ have been determined as a function of temperature, magnetic field and hydrostatic pressure by susceptibility and muon-spin spectroscopy measurements. From the data, fundamental microscopic parameters of the superconducting state like the London penetration depth λ, the gap values Δ, the upper critical field Bc₂, and the Ginzburg-Landau parameter κhave been obtained. In accordance with earlier measurements the ratio of the superfluid density nₛ ∝ λ⁻² to the superconducting transition temperature Tc=2.52(2) K at ambient pressure is found to be much larger in the strongly hole-overdoped RbFe₂As₂ than in high-Tc Fe-based and other unconventional superconductors. As a function of pressure Tc strongly decreases with a rate of dTc/dp = -1.32 K/GPa, i.e. it is reduced by 52 % at p = 1 GPa. The temperature dependence of nₛ is best described by a two gap s-wave model with both superconducting gaps being decreased by hydrostatic pressure until smaller gap completely disappears at p = 1 GPa.