Parity transition of spin-singlet superconductivity using sub-lattice degrees of freedom

Abstract

Recently, a superconducting (SC) transition from low-field (LF) to high-field (HF) SC states was reported in CeRh${}_2$As${}_2$, indicating the existence of multiple SC states. It has been theoretically noted that the existence of two Ce sites in the unit cell, the so-called sub-lattice degrees of freedom owing to the local inversion symmetry breaking at the Ce sites, can lead to the appearance of multiple SC phases even under an interaction inducing spin-singlet superconductivity. CeRh${}_2$As${}_2$ is considered as the first example of multiple SC phases owing to this sub-lattice degree of freedom. However, microscopic information about the SC states has not yet been reported. In this study, we measured the SC spin susceptibility at two crystallographically inequivalent As sites using nuclear magnetic resonance for various magnetic fields. Our experimental results strongly indicate a spin-singlet state in both SC phases. In addition, the antiferromagnetic phase, which appears within the SC phase, only coexists with the LF SC phase; there is no sign of magnetic ordering in the HF SC phase. The present work reveals unique SC properties originating from the locally noncentrosymmetric characteristics.

9 pages, 7 figures, including Supplementary Materials, selected as Editors' Suggestion

References in corpus (8)

• Superconducting order parameter in UTe${}_2$ determined by Knight shift measurement
• Observation of antiferromagnetic order as odd-parity multipoles inside the superconducting phase in CeRh${}_2$As${}_2$
• Two-dimensional XY-type Magnetic Properties of Locally Noncentrosymmetric Superconductor CeRh${}_2$As${}_2$
• Superconductivity in disordered locally noncentrosymmetric materials: an application to CeRh${}_2$As${}_2$
• Low-Temperature Thermal Conductivity of CeRh${}_2$As${}_2$
• Spin-Orbit Coupling in Multilayer Superconductors with Charge Imbalance
• Spatially Inhomogeneous Superconducting State near $H_{c2}$ in UPd${}_2$Al${}_3$
• Absence of the Pauli-Paramagnetic Limit in a Superconducting U${}_6$Co

Cited by in corpus (1)

• Discovery of magnetic phase transitions in heavy-fermion superconductor CeRh${}_2$As${}_2$