Concurrence of in-plane anisotropic superconductivity and quasi-one-dimensional charge density wave in layered CuTe under high pressure

Despite its layered orthorhombic lattice structure, CuTe hosts quasi-one-dimensional (quasi-1D) charge density wave (CDW) distortions of in-plane Te chains along the $a$ axis below ${T}_{\mathrm{CDW}}\ensuremath{\sim}346\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. This unique quasi-1D CDW manifests itself as an in-plane resistivity anisotropy, i.e., the $a$-axis resistivity (${\ensuremath{\rho}}_{a}$) displays an evident humplike anomaly below ${T}_{\mathrm{CDW}}$ while the $b$-axis resistivity (${\ensuremath{\rho}}_{b}$) is featureless. Herein, we present simultaneous measurements of ${\ensuremath{\rho}}_{a}$ and ${\ensuremath{\rho}}_{b}$ at various pressures to 16.0 GPa, in order to trace the quasi-1D CDW's evolution and its interplay with the induced superconductivity (SC). We found no sign of SC at ambient pressure from ${\ensuremath{\rho}}_{a}$ and ${\ensuremath{\rho}}_{b}$ with temperatures down to as low as 0.05 K. With the application of pressure, ${T}_{\mathrm{CDW}}$ from ${\ensuremath{\rho}}_{a}$ deceases linearly yet the quasi-1D CDW character of CuTe keeps unchanged with pressures to 6.4 GPa, above which it breaks down due to the formation of an isotropic electronic interaction-driven CDW. Meanwhile, a local superconducting pairing starts to nucleate at 3.9 GPa initially within the preexisting quasi-1D CDW Te chains (along the $a$ axis) at \ensuremath{\sim}0.4 K. For a given higher pressure, distinct discrepancies in the zero-resistance temperature and the upper critical field are observed, both of which disappear suddenly along with the CDW transformation. Such a rare observation of the in-plane anisotropic SC interlocking with the quasi-1D CDW in pressurized CuTe has been discussed in terms of the particular fermiology, local superconducting pairing, and strong CDW fluctuations that are all rooted in the quasi-1D, chainlike arrangement of its in-plane Te atoms.