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DOE OSTI · 2470362

Two-component nematic superconductivity in 4Hb-TaS 2

Silber, I.·Mathimalar, S.·Mangel, I.·Nayak, A. K.·Green, O.·Avraham, N.·Beidenkopf, H.·Feldman, I.·Kanigel, A.·Klein, A.·Goldstein, M.·Banerjee, A.·Sela, E.·Dagan, Y.
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Abstract

Most superconductors have an isotropic, single component order parameter and are well described by the standard (BCS) theory for superconductivity. Unconventional, multiple-component superconductors are exceptionally rare and are much less understood. Here, we combine scanning tunneling microscopy and angle-resolved macroscopic transport for studying the candidate chiral superconductor, 4Hb-TaS 2 . We reveal quasi-periodic one-dimensional modulations in the tunneling conductance accompanied by two-fold symmetric superconducting critical field. The strong modulation of the in-plane critical field, H c2 , points to a nematic, unconventional order parameter. However, the imaged vortex core is isotropic at low temperatures. We suggest a model that reconciles this apparent discrepancy and takes into account previously observed spontaneous time-reversal symmetry breaking at low temperatures. The model describes a competition between a dominating chiral superconducting order parameter and a nematic one. The latter emerges close to the normal phase. Our results strongly support the existence of two-component superconductivity in 4Hb-TaS 2 and can provide valuable insights into other systems with coexistent charge order and superconductivity.

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Silber, I., Mathimalar, S., Mangel, I., Nayak, A. K., Green, O., Avraham, N., Beidenkopf, H., Feldman, I., Kanigel, A., Klein, A., Goldstein, M., Banerjee, A., Sela, E., Dagan, Y.. 2024-01-27. Two-component nematic superconductivity in 4Hb-TaS 2. https://doi.org/10.1038/s41467-024-45169-3

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