Phys.org February 7, 2024
The discovery of superconductivity in infinite-layer nickelates established another category of unconventional superconductors that shares structural and electronic similarities with cuprates. However, key issues of the superconducting pairing symmetry, gap amplitude and superconducting fluctuations are yet to be addressed. A team of researchers in the US (Ames National Laboratory, SLAC National Laboratory, Stanford University) utilized static and ultrafast terahertz spectroscopy and demonstrated that the equilibrium terahertz conductivity and non-equilibrium terahertz responses of an optimally Sr-doped nickelate film are in line with the electrodynamics of d-wave superconductivity in the dirty limit. The gap-to-Tc ratio of 3.4 indicated that the superconductivity fell in the weak coupling regime. They also observed substantial superconducting fluctuations near Tc that did not extend into the deep normal state as the optimally hole-doped cuprates do. According to the researchers their results support a d-wave system that closely resembles the electron-doped cuprates… read more. TECHNICAL ARTICLE
Equilibrium THz conductivity of nickelate superconducting film… Credit: Nature Materials, January 5, 2024