Critical spin nature of the Cooper pairing of Nickelate superconductors: resembling cuprates, Moiré magic-angle graphene, and heavy-fermion UTe₂?

One of the ideal routes to unravel the high-T_c pairing mechanism in cuprates is through a ‘twin sister’ – a cuprate analogue, which mimics the electronic and structural templates. Standing beside copper in the periodic table, Ni¹⁺ in the infinite-layer phase hosts a 3d⁹ electronic structure - resembles the Cu²⁺ state in cuprates. Following the two decades debates, the recent experimental data suggests both significant similarities and distinctions to the high-T_c cuprates [1-5]. Surprisingly, some of these distinctions marked a close resemblance to the magic-angle Moiré multilayer graphene and heavy-fermion spin-triplet superconductor UTe₂. Particularly, we revealed a large Pauli-limit violation in all crystallographic directions, which suggests that nickelates may host both spin-singlet and spin-triplet pairing mechanisms. In this presentation, we will share our recent angular-dependent magnetotransport and spectroscopy data, and discuss the hidden connections between nickelate superconductor and the strongly-correlated cuprates, Moiré multilayer graphene, and spin-triplet UTe₂.



[1] A. S. Botana et. al., J. Exp. Theor. Phys. 132 (2021)

[2] L. E. Chow et. al., arXiv:2201.10038

[3] S. P. Harvey et. al., arXiv:2201.12971

[4] J. Fowlie et. al., Nat. Phys. 18 (2022)

[5] L. E. Chow et. al., arXiv:2204.12606