Manipulating and sensing microscopic spin density with quantum sensors

What is it about?

Represented by Nitrogen-Vacancy centers in diamonds, solid-state spin defects serve as precise sensors for detecting nanoscale magnetic signals, allowing them to probe local spin densities and intriguing dynamics within various materials. The charge state of spin defects is crucial—it not only establishes the spin but also influences the quantum sensor's coherence time, indicating how long quantum information is preserved. This study innovatively employs charge transport to adjust the spin density in surrounding environments and characterizes the changes in spin concentration through detailed spin bath spectrum measurements. The approach utilizes the cycling process of ionization and recombination of NV centers in diamonds to pump electrons from the valence band to the conduction band. These electrons are then transported to modulate the spin concentration by altering the defect's charge state. Spinless defects in the bath, such as positively charged nitrogen atoms, capture electrons and transform into spinning defects (P1 centers, electrically neutral), accomplishing the tuning of spin concentration in the bath. Additionally, the central NV spin is utilized to 'image' this dynamic process, thereby both manipulating and probing the bath

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Photo by Edgar Soto on Unsplash

Photo by Edgar Soto on Unsplash

Why is it important?

The spin-bath configuration in solid-state spin systems establishes them as a vital platform for studying quantum many-body physics. The central spin can polarize, control, and detect spins in the bath, while the spins in the bath, owing to their higher density, more readily exhibit quantum many-body effects. These insights open avenues for adjusting the spin concentration and, consequently, their interactions, providing opportunities to engineer and investigate intriguing many-body dynamics within solid-state spin systems.