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A CMOS silicon spin qubit
R. Maurand, X. Jehl, D. Kotekar Patil, A. Corna, H. Bohuslavskyi, R. Laviéville, L. Hutin, S. Barraud, M. Vinet, M. Sanquer, S. De Franceschi
TL;DR
CMOS-compatible silicon qubits could support scalable quantum processors and integration with classical control hardware. This paper demonstrates a CMOS-fabricated hole-spin qubit with electrical two-axis control and reaches a Rabi frequency of approximately 85 MHz.
Problem
The paper addresses the need for silicon qubit devices that leverage established CMOS fabrication and integration capabilities.
Method
The authors adapt an industry-standard CMOS process to fabricate a two-gate transistor containing a hole-spin quantum dot and a separate readout dot, with EDSR control.
Results
A phase-tunable microwave modulation achieves coherent electrical two-axis spin control with a Rabi frequency of approximately 85 MHz.
Takeaways & Limitations
The result supports CMOS technology as a viable platform for scaling silicon spin qubits.
Takeaways & Limitations
The observed coherence times are unlikely to be explained by Si29 nuclear-spin dephasing alone, suggesting other decoherence mechanisms may dominate.
Abstract
from arXiv · showhide
Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot (QD) encoding a hole spin qubit, the second one a QD used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. Our result opens a viable path to qubit up-scaling through a readily exploitable CMOS platform.
METHODS
Measurements were performed at 10 mK with filtered low-frequency lines and amplified direct source-drain readout. Microwave and gate-control signals were combined and applied through dedicated high-frequency wiring and pulse-generation electronics.
- Measurement setup: Measurements were performed in a dilution refrigerator at T = 10 mK.The direct source-drain current used for qubit readout was measured with a current/voltage amplifier.
- Measurement setup: The current/voltage amplifier used for direct source-drain readout had a gain of 109.Low-frequency lines were low-pass filtered at base temperature with two-stage RC filters.
- Signal delivery: Gate 1 received high-frequency signals through a 20 GHz bandwidth coaxial line with distributed 36 dBm attenuation.A home-made bias tee combined microwave and low-frequency signals on the gate.
- Qubit control sequence: An arbitrary wave generator produced two-level Vg1 modulation between Coulomb blockade for manipulation and Pauli blockade for readout and initialization.Additional AWG channels controlled the I and Q inputs of the microwave source.
- Signal combination: A diplexer combined microwave bursts with the two-level gate modulation before the signals reached the dilution refrigerator.The setup used three AWG channels for gate modulation and microwave I/Q control.