Tuning Electron Spin Coherence in Carbon Nanospheres through Defect Engineering

Area of Science:

• Materials Science
• Quantum Computing
• Spintronics

Background:

• Electron spin decoherence in carbon nanospheres (CNS) limits quantum device performance.
• Understanding the impact of structural defects on spin coherence is crucial.

Purpose of the Study:

• To develop and validate a model predicting spin decoherence time (T2) in CNS.
• To investigate the influence of defects on T2 and identify methods for enhancement.
• To extend the spin lifetime in CNS for improved quantum and spintronic applications.

Main Methods:

• Development of a simple analytical model for T2 prediction.
• Experimental validation of the model using CNS.
• Analysis of defect types (vacancies, impurities, chemisorption) and their distribution.
• Controlled annealing procedures to minimize defects and enhance coherence.

Main Results:

• The model accurately predicts T2, correlating it with defect concentration and distribution.
• Spin polarization is distributed over ~5 nm in CNS, with T2 ~200 ns.
• A confined annealing protocol extended T2 to 362 ns.

Conclusions:

• Defect minimization through controlled annealing is key to enhancing spin coherence in CNS.
• The findings provide guidelines for optimizing spin coherence time in quantum devices and spintronics.
• The developed model and protocol offer a pathway for improved CNS-based quantum technologies.