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Optical probes of two-component pairing states in transition metal dichalcogenides

Miguel-Ángel Sánchez-Martínez1,*, Daniel Muñoz-Segovia2,3, and Fernando de Juan2,4

  • *Contact author: contact@masanchezmartinez.com
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Phys. Rev. B 113, 054528 – Published 26 February, 2026

DOI: https://doi.org/10.1103/s1wd-25dz

Abstract

Signatures of unconventional superconductivity have been recently observed in certain transition metal dichalcogenides (TMDs), including 4Hb−TaS2 and monolayer 2H-NbSe2. While the pairing channel remains unknown, it has been argued that spin fluctuations can stabilize pairing in the two-component E′ channel, a p-wave spin-triplet state which could be consistent with some of the reported signatures. Exploiting the particular multiorbital character of the Fermi surface and the presence of Ising spin-orbit coupling, which enable finite optical conductivity in the clean limit, in this work we predict clear-cut optical signatures to detect and distinguish the chiral and nematic ground states of the E′ pairing. We quantify how nematic E′ states produce a diagonal anisotropy σxx≠σyy due to the broken threefold symmetry (C3), while chiral E′ states yield a finite optical Hall conductivity σxyH due to broken time-reversal symmetry, and find both signals could be detected in current experiments. For instance, for realistic gaps in the meV range, we predict a relative anisotropy Δσ/σ∼10−5 in the nematic states, and a polar Kerr rotation of θK∼10−5rad in the chiral states. These symmetry fingerprints provide a practical route to distinguish nematic and chiral superconducting order in TMD superconductors.

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Phys. Rev. B 113, 054528– Published 26 February, 2026
  • Received 27 March 2025
  • Revised 30 November 2025
  • Accepted 29 January 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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