4Hb-TaS₂ is a naturally formed quasi-two-dimensional heterojunction material composed of alternating monolayers of insulating ($1T$-) and superconducting ($1H$-) TaS₂. We report on a comprehensive high-pressure study on the interplay between charge-density wave (CDW) and superconductivity (SC) in 4Hb-TaS₂. The results uncover a dome-shaped strong-coupling superconductor on the border of a 3 ×{} 3 commensurate CDW at Pc1≈2.0 GPa: (1) nearly one order enhancement of upper critical field Bc2(0); (2) the derived 2Δ₀/kBTc beyond the BCS theory, decaying to a conventional one above 4.5 GPa; (3) the exponent of normal-state resistivity n≈1.50 and triply enhanced electronic effective mass. Under pressure, a third CDW emerging from 2.0 GPa is related to the original two CDWs, then disappears above 11.5 GPa. The temperature dependence of Bc2(T) collapses into a universal curve and the comparison of Bc2(T) to a polar-state function in 4Hb-TaS₂. Theoretical calculations proposed the stronger interlayer coupling and band hybridization responsible for strong-coupling SC; the suppression of new CDWs is related to band inversions between the $1T$-Ta-dxy (GM1+) and S-pz bands (GM2-) at the ΓA point; above 5.0 GPa, the coexisting weak-coupling SC and linear magnetoresistance can be attributed to the formation of electronic bands along the M-K lines and the ΓA point. Our discovery provides an excellent example to demonstrate the interplay of the strong-coupling superconducting state and topological electronic state in van der Waals heterojunctions.
No takes yet. Share an insight, caveat, or question.
Xu et al. (2024) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: