Low-temperature anomaly and anisotropy of critical magnetic fields in transition-metal dichalcogenide superconductors

Fuente: arXiv
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Main Authors: Sano, Tomoya, Tabata, Kota, Sasaki, Akihiro, Asano, Yasuhiro
Format: Preprint
Published: 2026
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author Sano, Tomoya
Tabata, Kota
Sasaki, Akihiro
Asano, Yasuhiro
author_facet Sano, Tomoya
Tabata, Kota
Sasaki, Akihiro
Asano, Yasuhiro
contents We clarify why spin-singlet superconductivity persists in monolayer transition-metal dichalcogenides even in high magnetic fields beyond the Pauli limit. The phenomenon called Ising protection is caused by two magnetically active potentials: a Zeeman field and an Ising spin-orbit interaction. These potentials induce two spin-triplet pairing correlations in a spin-singlet superconductor. One belonging to odd-frequency symmetry class arises solely from a Zeeman field and always makes the superconducting state unstable. The other belonging to even-frequency symmetry class arise from the interaction between the two magnetic potentials and eliminate the instability caused by odd-frequency pairs. The presence or absence of even-frequency spin-triplet pairs explains the anisotropy of the Ising protection. The analytical expression of the superfluid weight enables us to conclude that even-frequency spin-triplet Cooper pairs support spin-singlet superconductivity in high Zeeman fields.
format Preprint
id arxiv_https___arxiv_org_abs_2601_20288
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Low-temperature anomaly and anisotropy of critical magnetic fields in transition-metal dichalcogenide superconductors
Sano, Tomoya
Tabata, Kota
Sasaki, Akihiro
Asano, Yasuhiro
Superconductivity
We clarify why spin-singlet superconductivity persists in monolayer transition-metal dichalcogenides even in high magnetic fields beyond the Pauli limit. The phenomenon called Ising protection is caused by two magnetically active potentials: a Zeeman field and an Ising spin-orbit interaction. These potentials induce two spin-triplet pairing correlations in a spin-singlet superconductor. One belonging to odd-frequency symmetry class arises solely from a Zeeman field and always makes the superconducting state unstable. The other belonging to even-frequency symmetry class arise from the interaction between the two magnetic potentials and eliminate the instability caused by odd-frequency pairs. The presence or absence of even-frequency spin-triplet pairs explains the anisotropy of the Ising protection. The analytical expression of the superfluid weight enables us to conclude that even-frequency spin-triplet Cooper pairs support spin-singlet superconductivity in high Zeeman fields.
title Low-temperature anomaly and anisotropy of critical magnetic fields in transition-metal dichalcogenide superconductors
topic Superconductivity
url https://arxiv.org/abs/2601.20288