We report the discovery of two-phase 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. More detailed analysis identifies the transition from the low- to high-field states to be associated with one between states of even and odd parity.
@article{arxiv.2101.09522,
title = {Field-induced transition from even to odd parity superconductivity in CeRh$_2$As$_2$},
author = {S. Khim and J. F. Landaeta and J. Banda and N. Bannor and M. Brando and P. M. R. Brydon and D. Hafner and R. Küchler and R. Cardoso-Gil and U. Stockert and A. P. Mackenzie and D. F. Agterberg and C. Geibel and E. Hassinger},
journal= {arXiv preprint arXiv:2101.09522},
year = {2021}
}