Quantum Café Webinar: James Analytis

Tuesday May 18, 2021, 11:15 AM → 12:15 PM America/New_York

Title: Superconductivity and quantum criticality linked by the Hall effect in a strange metal

Abstract: Many unconventional superconductors exhibit a common set of anomalous charge transport properties that charac- terize them as ‘strange metals’, which provides hope that there is a single theory that describes them1–3. However, model-independent connections between the strange met- als and superconductivity have remained elusive. Here, we show that the Hall effect of the unconventional superconduc- tor BaFe2(As1−xPx)2 contains an anomalous contribution aris- ing from the correlations within the strange metal. This term has a distinctive dependence on the magnetic field, which allows us to track its behaviour across the doping–tempera- ture phase diagram, even under the superconducting dome. These measurements demonstrate that the strange metal Hall component emanates from a quantum critical point and, in the zero-temperature limit, decays together with the super- conducting critical temperature. This empirically reveals the structure of the connection between superconductivity and quantum criticality, which may be common to the physics of many strange metal superconductors.