Microwave quantum circuits with van der Waals cuprate heterostructures

• Applicants: Privatdozent Nicola Poccia, Ph.D.; Dr. Uri Vool
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 539383397

We will engineer a new generation of the van der Waals cuprate heterostructures comprising atomically thin Bi2Sr2Can-1CunO2n+4 (where n = 1,2,3) crystals with another superconducting technology: microwave quantum circuits. By creating hybrid fully-superconducting circuits which combine van der Waals flakes and thin film microwave resonators, we will be able to use circuit coherence to study the superfluid density and the structure of the inducted superconducting gap in the heterostructure interface at different twist angles. The central challenges of this project are that it is generally difficult to make high-quality contacts with such air-sensitive materials, and standard electrical transport measurements are often insufficient to understand their internal structure and limit the devices that can be built. To overcome the challenge of contacting the material, particularly for superconducting contacts, we will develop a via contact through a nanomembrane. Microwave resonant circuits will be fabricated on the nanomembrane itself, allowing for high-quality hybrid circuits. This technique will allow us to study the properties of new induced superconducting phases in van der Waals heterostructures, as well as a starting point for general van der Waals superconducting quantum technology devices.

• DFG Programme: Research Grants