Tuning Electron Spin Coherence in Carbon Nanospheres through Defect Engineering.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40699936.
- Also identified by DOI 10.1021/acsnano.5c07050 and PMC identifier 12333433.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
This study investigates spin decoherence in large disordered carbon nanosphere (CNS) particles with a focus on predicting and extending the electron spin qubit decoherence time (<i>T</i><sub>2</sub>). We present and experimentally validate a simple analytical model that predicts <i>T</i><sub>2</sub> and reveal how defects─such as carbon vacancies, hydrogen chemisorption, and substitutional impurities─along with their concentration and distribution, impact <i>T</i><sub>2</sub>. This model offers insights into the interplay among spin density distribution, structural defects, and isotopic composition, demonstrating the role of defect minimization through controlled annealing in enhancing spin coherence. Through comparison with experimental data, we validate our model and demonstrate that spin polarization in the CNS is likely evenly distributed over a characteristic region of approximately 5 nm for <i>T</i><sub>2</sub> ∼ 200 ns. Based on these findings, we propose a synthetic protocol involving a confined annealing procedure that extends the spin lifetime in the CNS to up to 362 ns. With observed improvements in <i>T</i><sub>2</sub>, our findings provide valuable guidelines for optimizing electron spin coherence time in quantum devices and spintronic applications.