The natural bulk Van der Waals heterostructure compound $6R\text{−}{\mathrm{TaS}}_2$ consists of alternate stacking $1T$- and $1H\text{−}{\mathrm{TaS}}_2$ monolayers, creating a unique system that incorporates charge-density-wave (CDW) order and superconductivity (SC) in distinct monolayers. Here, after confirming that the 2D nature of the lattice is preserved up to 8 GPa in $6R\text{−}{\mathrm{TaS}}_2$, we documented an unusual evolution of CDW and SC by conducting high-pressure electronic transport measurements. Upon compression, we observe a gradual suppression of CDW within the $1T$ layers, while the SC exhibits a dome-shaped behavior that terminates at a critical pressure $P_{\mathrm{c}}$ around 2.9 GPa. By taking account of the fact that the substantial suppression of SC is concomitant with the complete collapse of CDW order at $P_{\mathrm{c}}$, we argue that the $6R\text{−}{\mathrm{TaS}}_2$ behaves like a stack of Josephson junctions and thus the suppressed superconductivity can be attributed to the weakening of Josephson coupling associated with the presence of CDW fluctuations in the $1T$ layers. Furthermore, the SC reversely enhances above $P_{\mathrm{c}}$, implying the development of emergent superconductivity in the $1T$ layers after the melting of $T$-layer CDW orders. These results show that the $6R\text{−}{\mathrm{TaS}}_2$ not only provides a promising platform to explore emergent phenomena but also serves as a model system to study the complex interactions between competing electronic states.

Close

PrevNext

View figure in article

• Charge density waves
• Pressure effects
• Superconductivity
• Strongly correlated systems
• Transition metal dichalcogenides