Pairing-channel reconstruction by Ising spin-orbit coupling in a multiorbital triangular-lattice model
Abstract
Ising spin-orbit coupling (SOC) is widely known for locking electronic spins and protecting superconductivity against in-plane paramagnetic pair breaking. Here we show that, in a correlated multiorbital system, Ising SOC can play a qualitatively different role: it reconstructs the hierarchy of spin-fluctuation-mediated pairing channels by reshaping the low-energy Fermi surfaces, orbital-spin coherence factors, and momentum-resolved scattering phase space. We study a noncentrosymmetric two-orbital triangular-lattice model with Rashba SOC, Ising SOC, and onsite SOC. We solve the pairing problem within a multiorbital random-phase-approximation framework. In the single-orbital limit, an E-representation state with a dominant Sz=0 component emerges only at relatively strong Ising SOC. Orbital degrees of freedom facilitate the stabilization of this pairing state at a smaller nominal Ising SOC strength and generate a broad competition between E and A1 pairing channels. The E state can maintain the same Sz=0 triplet character, whereas the A1 state becomes a fully gapped sign-changing splusminus superconductor. The latter also realizes a topologically nontrivial phase in the time-reversal-invariant weak-pairing regime, with a nonzero ℤ2 index, Wilson-loop spectral flow, and boundary modes. Its topology is not carried by a single orbital pairing component, but emerges cooperatively from the dominant intra- and inter-orbital pairing components. These results establish a microscopic route by which Ising SOC and orbital hybridization can reconstruct interaction-driven superconductivity, producing both Ising-triplet and topological singlet-dominated phases in correlated non-centrosymmetric systems.
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BibTeX
@misc{wang2026pairingchannel,
title = {{Pairing-channel reconstruction by Ising spin-orbit coupling in a multiorbital triangular-lattice model}},
author = {Lichuan Wang and Yuhang Xiao and Ran Wang and Xinliang Huang and Ning Hao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21369},
eprint = {2610.21369},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21369},
}
RIS
TY - UNPB
TI - Pairing-channel reconstruction by Ising spin-orbit coupling in a multiorbital triangular-lattice model
AU - Lichuan Wang
AU - Yuhang Xiao
AU - Ran Wang
AU - Xinliang Huang
AU - Ning Hao
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21369
UR - https://arxiv.org/abs/2610.21369
AB - Ising spin-orbit coupling (SOC) is widely known for locking electronic spins and protecting superconductivity against in-plane paramagnetic pair breaking. Here we show that, in a correlated multiorbital system, Ising SOC can play a qualitatively different role: it reconstructs the hierarchy of spin-fluctuation-mediated pairing channels by reshaping the low-energy Fermi surfaces, orbital-spin coherence factors, and momentum-resolved scattering phase space. We study a noncentrosymmetric two-orbital triangular-lattice model with Rashba SOC, Ising SOC, and onsite SOC. We solve the pairing problem within a multiorbital random-phase-approximation framework. In the single-orbital limit, an E-representation state with a dominant S_z=0 component emerges only at relatively strong Ising SOC. Orbital degrees of freedom facilitate the stabilization of this pairing state at a smaller nominal Ising SOC strength and generate a broad competition between E and A_1 pairing channels. The E state can maintain the same S_z=0 triplet character, whereas the A_1 state becomes a fully gapped sign-changing splusminus superconductor. The latter also realizes a topologically nontrivial phase in the time-reversal-invariant weak-pairing regime, with a nonzero ℤ_2 index, Wilson-loop spectral flow, and boundary modes. Its topology is not carried by a single orbital pairing component, but emerges cooperatively from the dominant intra- and inter-orbital pairing components. These results establish a microscopic route by which Ising SOC and orbital hybridization can reconstruct interaction-driven superconductivity, producing both Ising-triplet and topological singlet-dominated phases in correlated non-centrosymmetric systems.
ER -