Mechanically Exfoliated Metallic Delafossite PdCoO2 Nanomembranes: Quantum Transport and Electrical Evaluation toward Interconnect Applications

Abstract

Metallic delafossite oxides have drawn attention for their ultralow resistivity and coherent electronic transport. However, mesoscopic transport studies are hindered by the limited access to high-quality nanoscale devices. Here, we report single-crystalline PdCoO2 nanomembranes, enabling exploration of quasi-two-dimensional (quasi-2D) transport. Shubnikov-de Haas and angle-dependent h/e magnetoresistance oscillations under different magnetic field directions are observed at low temperatures, from which the electron effective mass is extracted. Beyond quantum transport, the electrical performance of PdCoO2 toward interconnect applications is evaluated. A nearly thickness-independent room-temperature resistivity is observed for flakes down to 40 nm thickness. The nanomembranes exhibit a breakdown current density up to 113 MA cm–2, with excellent thermal stability and electromigration resistance. These results demonstrate that mechanically exfoliated PdCoO2 flakes preserve the high crystalline and electronic quality of bulk crystals in the quasi-2D limit, providing a useful platform for mesoscopic transport studies and interconnect applications.