Two-phase superconductivity in CeRh2As2 and the role of Rashba spin-orbit coupling

Andrew Mackenzie

I will describe the work of colleagues in my Institute and beyond on the discovery of twophase unconventional superconductivity in CeRh2As2. Using thermodynamic probes, we establish that the superconducting critical field of its high-field phase is as high as 14 T, remarkable in a material whose transition temperature is 0.26 K. Furthermore, a c-axis field drives a transition between two different superconducting phases. In spite of the fact that CeRh2As2 is globally centrosymmetric, we show that local inversion symmetry breaking at the Ce sites enables Rashba spin-orbit coupling to play a key role in the underlying physics.