Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform

作者： Kaveh Delfanazari1,2, Pengcheng Ma2, Reuben Puddy2, Teng Yi2, Moda Cao2, Yilmaz Gul3, Carly L. Richardson4, Ian Farrer2,5, David Ritchie2, Hannah J. Joyce1, Michael J. Kelly1,2, Charles G. Smith2 1Centre for Advanced Photonics and Electronics, Engineering Department,University of Cambridge, 2Department of Physics, Cavendish Laboratory,University of Cambridge, 3Department of Electronic and Electrical Engineering,University College London, 4Department of Materials Science and Metallurgy,University of Cambridge, 5Department of Electronic and Electrical Engineering,University of Sheffield

简介：

Overview

This study demonstrates quantum integrated circuits (QICs) utilizing planar and ballistic Josephson junctions (JJs) based on In_0.75Ga_0.25As two-dimensional electron gas (2DEG). The fabrication methods for the 2D JJs and QICs are discussed, along with quantum transport measurements conducted at sub-Kelvin temperatures.

Key Study Components

Area of Science

• Quantum integrated circuits
• Josephson junctions
• Two-dimensional materials

Background

• Hybrid superconductor-semiconductor junctions require a homogeneous interface.
• Indium gallium arsenide serves as a platform for studying superconductivity.
• Quantum transport measurements are essential for characterizing device performance.
• Sub-Kelvin temperatures are critical for observing quantum phenomena.

Purpose of Study

• To explore the proximity-induced superconductivity in 2DEG.
• To fabricate and characterize two-dimensional Josephson junctions.
• To investigate the effects of junction dimensions on topological phases.

Methods Used

• Fabrication of JJs and QICs using photolithography and etching techniques.
• Electrical contact formation through ohmic pads.
• Transport measurements in a dilution refrigerator.
• Characterization of devices using scanning electron microscopy (SEM).

Main Results

• Demonstration of subharmonic energy gap structures in Device 1.
• Temperature-dependent behavior of superconducting gaps observed.
• Device 2 showed no in-gap oscillations, contrasting with Device 1.
• Successful measurement of multiple quantum devices in a single cooldown.

Conclusions

• Two-dimensional Josephson junctions can be effectively studied.
• Device fabrication techniques enable scalable quantum device development.
• Temperature and magnetic field dependencies provide insights into superconductivity.

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