Pressure-Induced Enhancement of Superconductivity in 3R-TaSe2 Single Crystals

Layered transition-metal dichalcogenides provide an ideal platform to explore the competition between charge-density-wave (CDW) order and superconductivity. The 3R-stacked TaSe2 hosts intrinsic CDW and superconductivity without chemical doping, yet systematic high-pressure experimental evidence remains lacking. Here, we report on systematic studies of pressure phase diagrams of up to 2 GPa in high-quality single crystals of 3R-TaSe2. At ambient pressure, a CDW transition emerges near 100 K and bulk superconductivity onset occurs at Tc ≈ 2.8 K. Upon hydrostatic compression, the CDW transition temperature is monotonically suppressed, while Tc increases to ~3.1 K at 2 GPa, clearly revealing an antagonistic relationship between these two quantum phases. Hall and thermopower measurements suggest CDW-driven Fermi-surface reconstruction and single-band carrier behavior. From pressure-dependent transport, we construct the P(T) phase diagram, and anisotropic upper-critical-field data demonstrate quasi-two-dimensional superconductivity in bulk 3R-TaSe2. This work offers key experimental insights into competing correlated states in van der Waals layered materials.