Tuning superconductivity and charge density wave order in TaSe2 through Pt intercalation

Tantalum diselenide (TaSe2) has emerged as a promising platform to investigate the interplay between two intriguing quantum electronic states in materials: the charge density wave order (CDW) and superconductivity. In this work, we report the ability to tune these quantum electronic states by intercalating Pt into 2H-TaSe2. By introducing 20% of Pt into 2H-TaSe2, we demonstrate that the structural phase changes from the 2H to the 4Hb phase of TaSe2 with Pt atoms intercalated within the van der Waals spacing. According to the Fermi surface of the 4Hb phase, a Lifshitz transition occurred, destroying the Fermi-surface nesting found in the 2H phase. This can be attributed to the structural phase transformation and the influence of donated electrons from Pt, thus tuning the Van Hove singularities into the Fermi-level vicinity, suppressing the CDW state, and enhancing the superconducting temperature (Tc) to similar to 2.7 K. The resulting superconducting properties of the 4Hb-Pt0.2TaSe2 are consistent with those of a BCS type-II superconductor, with a superconducting gap of 3.0 meV. Our results provide insights into the role of electron doping and structural phase changes in fine-tuning quantum electronic -state phenomena in materials. These findings could have significant implications in designing superconducting materials with tailored properties for practical applications.