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

Abstract

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 TCDW∼346K. This unique quasi-1D CDW manifests itself as an in-plane resistivity anisotropy, i.e., the a-axis resistivity (ρa) displays an evident humplike anomaly below TCDW while the b-axis resistivity (ρb) is featureless. Herein, we present simultaneous measurements of ρa and ρb 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 ρa and ρb with temperatures down to as low as 0.05 K. With the application of pressure, TCDW from ρa 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 ∼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.

Source-reported materials — not catalogue approval

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