Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits substantially over the past two decades. Here, we show by improving interface between InAs as a semiconductor and Al as a superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. We find that bandgap engineering is crucial in realizing a two-dimensional electron gas near the surface. In addition, we show how the coupling between the semiconductor layer and the superconducting contacts can affect qubit properties. We present the anharmonicity and coupling strengths from one and two-photon absorption in a quantum two level system fabricated with a JJ-FET. Published under license by AVS.

Automated summary

Improvements in interface between InAs semiconductor and Al superconductor have led to the fabrication of a voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. Bandgap engineering plays a crucial role in realizing a two-dimensional electron gas near the surface, while the coupling between the semiconductor layer and superconducting contacts affects qubit properties. Published research highlights the anharmonicity and coupling strengths in a quantum two level system fabricated with a JJ-FET.