Direct evidence for a pressure-induced nodal superconducting gap in the Ba0.65Rb0.35Fe2As2 superconductor

• DOI: 10.1038/ncomms9863
• Publication Date: 2015-11-09T10:04:59Z
• Authors: Z. Guguchia; A. Amato; J. Kang; H. Luetkens; P. K. Biswas; G. Prando; F. von Rohr; Z. Bukowski; A. Shengelaya; H. Keller; E. Morenzoni; Rafael M. Fernandes; R. Khasanov
• Keywords: Hydrostatic pressure; Muon spin spectroscopy

Abstract The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. In contrast to other unconventional superconductors, the Fe-HTSs both d -wave and extended s pairing symmetries are close energy. Probing proximity between these very different states identifying experimental parameters that can tune them of central interest. Here we report high-pressure muon spin rotation experiments on temperature-dependent magnetic penetration depth optimally doped nodeless Fe-HTS Ba 0.65 Rb 0.35 Fe 2 As . Upon pressure, a strong decrease zero-temperature limit observed, while transition temperature remains nearly constant. More importantly, low-temperature behaviour inverse-squared depth, which direct measure superfluid density, changes qualitatively from an exponential saturation at zero pressure linear-in-temperature higher pressures, indicating hydrostatic promotes appearance nodes gap.