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arXiv · 2101.08821

Unusual $H$-$T$ phase diagram of CeRh$_2$As$_2$ -- the role of staggered non-centrosymmetricity

Eric G. Schertenleib·Mark H. Fischer·Manfred Sigrist
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Abstract

Superconductivity in a crystalline lattice without inversion is subject to complex spin-orbit-coupling effects, which can lead to mixed-parity pairing and an unusual magnetic response. In this study, the properties of a layered superconductor with alternating Rashba spin-orbit coupling in the stacking of layers, hence (globally) possessing a center of inversion, is analyzed in an applied magnetic field, using a generalized Ginzburg-Landau model. The superconducting order parameter consists of an even- and an odd-parity pairing component which exchange their roles as dominant pairing channel upon increasing the magnetic field. This leads to an unusual kink feature in the upper critical field and a first-order phase transition within the mixed phase. We investigate various signatures of this internal phase transition. The physics we discuss here could explain the recently found $H$--$T$ phase diagram of the heavy Fermion superconductor CeRh$_2$As$_2$.

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Eric G. Schertenleib, Mark H. Fischer, Manfred Sigrist. 2021-01-21. Unusual $H$-$T$ phase diagram of CeRh$_2$As$_2$ -- the role of staggered non-centrosymmetricity. https://doi.org/10.1103/physrevresearch.3.023179

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