Two-component nematic superconductivity in 4Hb-TaS 2

• Published in: Nature communications Vol. 15; no. 1; p. 824
• Main Authors: 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
• Format: Journal Article
• Language: English
• Published: England 27.01.2024
• ISSN: 2041-1723

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 . 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 , 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 and can provide valuable insights into other systems with coexistent charge order and superconductivity.