Field-induced transition from even to odd parity superconductivity in CeRh$_2$As$_2$

S. Khim; J. F. Landaeta; J. Banda; N. Bannor; M. Brando; P. M. R. Brydon; D. Hafner; R. Küchler; R. Cardoso-Gil; U. Stockert; A. P. Mackenzie; D. F. Agterberg; C. Geibel; E. Hassinger

doi:10.1126/science.abe7518

arXiv · 2101.09522

Field-induced transition from even to odd parity superconductivity in CeRh$_2$As$_2$

S. Khim·J. F. Landaeta·J. Banda·N. Bannor·M. Brando·P. M. R. Brydon·D. Hafner·R. Küchler·R. Cardoso-Gil·U. Stockert·A. P. Mackenzie·D. F. Agterberg·C. Geibel·E. Hassinger

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Abstract

We report the discovery of two-phase unconventional superconductivity in CeRh$_2$As$_2$. 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 CeRh$_2$As$_2$ 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.

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S. Khim, J. F. Landaeta, J. Banda, N. Bannor, M. Brando, P. M. R. Brydon, D. Hafner, R. Küchler, R. Cardoso-Gil, U. Stockert, A. P. Mackenzie, D. F. Agterberg, C. Geibel, E. Hassinger. 2021-01-23. Field-induced transition from even to odd parity superconductivity in CeRh$_2$As$_2$. https://doi.org/10.1126/science.abe7518

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