Single-Electron Occupation in Quantum Dot Arrays at Selectable Plunger Gate Voltage

Area of Science:

• Quantum Computing
• Semiconductor Physics

Background:

• Semiconductor qubits offer a small footprint for scalable quantum computing.
• Qubit size sensitivity to local environment and gate variations challenges scalability.
• Current methods require tailored gate voltages for each device, hindering mass production.

Purpose of the Study:

• To develop a scalable method for tuning gate voltages in semiconductor qubits.
• To achieve stable charge states in quantum dots using a novel voltage equalization technique.

Main Methods:

• Utilized temporary application of stress voltages to tune and equalize gate voltages.
• Investigated charge state stability in a double quantum dot.
• Extended the method to a 2x2 quadruple quantum dot configuration.

Main Results:

• Achieved a stable (1,1) charge state in a double quantum dot at identical, predetermined plunger gate voltages.
• Demonstrated the (1,1,1,1) charge state in a 2x2 quadruple quantum dot with all plunger gates set to 1 V.
• Showcased the ability to define required gate voltages irrespective of interdot couplings.

Conclusions:

• The stress voltage method offers a scalable solution for gate voltage control in quantum dots.
• This technique can simplify control electronics and operations for spin qubit devices.
• The findings represent a significant advancement in developing robust quantum hardware.