Electron spin resonance and spin-valley physics in a silicon double quantum dot

Area of Science:

• Quantum computing
• Solid-state physics
• Materials science

Background:

• Silicon quantum dots are promising for solid-state quantum bits.
• The multi-valley nature of silicon presents challenges for quantum bit development.

Purpose of the Study:

• To investigate electron spin resonance in a silicon CMOS-based double quantum dot.
• To understand the impact of silicon's multi-valley nature on quantum bit performance.
• To explore spin-valley mixing and its implications for qubit control.

Main Methods:

• Transport measurements of individual electrons in a silicon CMOS-based double quantum dot.
• Application of electron spin resonance (ESR) to probe energy levels.
• Analysis of anticrossing phenomena to quantify spin-valley interactions.

Main Results:

• Observed an anticrossing of energy levels when Zeeman and valley splittings align.
• Measured a 60 MHz anticrossing splitting, indicating spin and valley mixing.
• Extracted a lower bound for spin dephasing time of 63 ns.
• Provided evidence for unconventional spin-valley blockade despite non-ideal interfaces.

Conclusions:

• Spin-orbit interaction and non-ideal interfaces facilitate spin-valley mixing in silicon quantum dots.
• Understanding silicon spin-valley physics is key to improving spin qubit control and readout.
• This research supports the development of all-CMOS silicon-based quantum computing approaches.