in the Two-dimensional Limit*

As superconductors are thinned down to the 2D limit, their critical temperature T_c typically decreases. Here we report the opposite behavior, an enhancement of T_c with decreasing thickness, in the 2D crystalline superconductor 2H-TaS₂. Remarkably, in the monolayer limit, T_c increases by over a factor of four compared to bulk crystals. Accompanying this trend in superconductivity, we observe progressive weakening and suppression of the charge-density wave (CDW) transition with decreasing thickness. To explain these trends, we perform electronic structure calculations showing that a reduction of the CDW amplitude results in a substantial increase of the density of states at the Fermi energy, which contributes to the enhancement of T_c.
Our results provide insights into superconductivity, CDW order, and their mutual interaction in reduced dimensions.