Superconducting gatemon qubit based on a proximitized two-dimensional electron gas.

Area of Science:

• Quantum computing
• Superconducting circuits
• Condensed matter physics

Background:

• Josephson junctions (JJs) are crucial for superconducting quantum processors, providing nonlinear inductance for qubit control and readout.
• Current methods for JJ inductance control involve physical dimension tuning or magnetic flux biasing.
• Superconductor-semiconductor hybrid JJs offer an all-electric tuning alternative, with the gatemon being a recent transmon variant.

Purpose of the Study:

• To demonstrate the viability of wafer-scale two-dimensional electron gas (2DEG) as a platform for scalable gatemon-based quantum computing.
• To show that 2DEG gatemons meet the requirements for quantum information processing.

Main Methods:

• Fabrication of gatemons using semiconducting channels etched from a wafer-scale 2DEG.
• Performing voltage-controlled single-qubit rotations.
• Executing two-qubit swap operations.

Main Results:

• Demonstrated voltage-controlled single-qubit rotations and two-qubit swap operations using 2DEG gatemons.
• Achieved qubit coherence times up to approximately 2 microseconds.
• Identified dielectric loss in the 2DEG substrate as the limiting factor for coherence.

Conclusions:

• Wafer-scale 2DEG is a suitable platform for building scalable gatemon-based quantum computers.
• 2DEG gatemons enable all-electric control of quantum operations.
• Further improvements in substrate dielectric properties are needed to enhance qubit coherence times.