On-Device Synthesis of PdTe Thin Flakes with 2D Nature of Superconductivity

Abstract

Transition metal chalcogenides (TMCs) are emerging as platforms for exploring exotic phenomena such as topological physics and superconductivity. PdTe, as one of such materials, has recently been regarded as a candidate for Dirac semimetal and unconventional superconductivity. The superconducting behavior of PdTe from the bulk and the surface varies, thus a comparison between PdTe thin flakes and bulk materials is necessary. Due to the scarcity of reports on pure PdTe thin flakes, this study develops an in situ on-device synthesis process. First, a PdTe₂ bulk is exfoliated into thin flakes and fabricated into a transport device. Subsequently, an electrochemical process is carried out on this device to in situ transform the layered material PdTe₂ to non-layered material PdTe, forming a high-quality pure PdTe flake device. The critical temperature onset ($T_C^{\mathrm{onset}}$) of the flake (≈3.2 K) is lower than that of the bulks (≈4.4 K), while the values and the anisotropy of the upper critical fields (H_C2) are enhanced, demonstrating the characteristics of 2D superconductivity which are distinct from those of the bulks. This work provides a platform for studying the superconductivity of PdTe thin flakes and offers an approach for investigating candidates for unconventional superconductivity.