Effects of Lifshitz transitions in ferromagnetic superconductors: the case of URhGe
journal contributionposted on 12.09.2018, 10:55 by Yury Sherkunov, Andrey Chubukov, Joseph Betouras
In ferromagnetic superconductors, like URhGe, superconductivity co-exists with magnetism near zero field, but then re-appears again in a finite field range, where the system also displays mass enhancement in the normal state. We present theoretical understanding of this non-monotonic behavior. We explore the multi-band nature of URhGe and associate re-entrant superconductivity and mass enhancement with the finite field Lifshitz transition in one of the bands. We found good agreement between our theory and a number of experimental results for URhGe, such as weakly first order reentrant transition, the dependence of superconducting $T_c$ on a magnetic field, and the field dependence of the effective mass, the specific heat and the resistivity in the normal state. Our theory can be applied to other ferromagnetic multi-band superconductors.
This work was supported by the EPSRC (YS and JJB) through the grant EP/P002811/1. and by the U.S. Department of Energy through the University of Minnesota Center for Quantum Materials, under award DE-SC-0016371 (A.V.C.).