Development of KTaO₃-based superconducting parametric amplifiers

The recent discovery of superconductivity in KTaO₃ (KTO)-based two dimensional electron gas (2DEG) has raised wide interest [1]. Using conductive atomic microscope lithography, we have patterned KTO-based superconducting weak links (WLs) and SQUIDs, which reveal the high kinetic inductance of its superconducting 2DEG [2]. The unusual inductive and capacitive properties of KTO make it a potential platform for various kinds of superconducting microwave circuits. Here we present our work towards characterizing kinetic inductance as well as dielectric loss tangent of KTO 2DEG using a microwave resonator [3]. We also report our attempts to realize a new type of parametric amplifier based on KTO where pumping is sent through the gate near a KTO weak link.

[1] Changjiang Liu, et al. Science 371, 716-721 (2021)

[2] Muqing Yu, et al. arXiv:2310.16051 (2023)

[3] S. Mallik, et al. Nat Commun 13, 4625 (2022)