Isotropic Quantum Scattering and Unconventional Superconductivity

摘要

Superconductivity without phonons has been proposed for strongly correlatedelectron materials that are tuned close to a zero-temperature magneticinstability of itinerant charge carriers. Near this boundary, quantumfluctuations of magnetic degrees of freedom assume the role of phonons inconventional superconductors, creating an attractive interaction that glueselectrons into superconducting pairs. Here we show that superconductivity canarise from a very different spectrum of fluctuations associated with a local orKondo-breakdown quantum-critical point that is revealed in isotropic scatteringof charge carriers and a sub-linear temperature-dependent electricalresistivity. At this critical point, accessed by applying pressure to thestrongly correlated, local-moment antiferromagnet CeRhIn5, magnetic and chargefluctuations coexist and produce electronic scattering that is maximal at theoptimal pressure for superconductivity. This previously unanticipated source ofpairing glue opens possibilities for understanding and discovering newunconventional forms of superconductivity.