Dynamics of spin thermalization

Image represents a system of nuclear spins whose interactions are mediated by electron spins. Credit: The City University of New York

A group of researchers based at The City College of New York (CCNY) provide new insights on the dynamics of spin thermalization at the nanoscale. Understanding why this happens and how it can be controlled is presently at the center of a broad effort, particularly for applications in the emerging field of quantum information technologies.

One of the main hurdles to investigating nanoscale thermalization is the huge disparity between the numbers of thermal and athermal spins, the latter being only a tiny fraction of the total. To show the flow of spin polarization between these groups, experiments must be simultaneously sensitive to both groups, a difficult proposition as most techniques are adapted to one group or the other but ill-suited for both.

For example in diamond, because the electron spin is much stronger than the nuclear spin, carbons close to NVs or P1s experience a local magnetic field, absent for carbons that are farther away. Because of the local field they experience, hyperfine-coupled carbons have been traditionally assumed to be isolated from the rest, in the sense that, if polarized, they cannot pass this polarization to the bulk, i.e., their spin is frozen or ‘localized,” hence leading to an ‘athermal’ behavior.

Overall, the CCNY team’s findings could help realize devices that use electron and nuclear spins in solids for quantum information processing or sensing at the nanoscale. Indirectly, it could also help implement states of high nuclear spin polarization that could be applied in MRI and NMR spectroscopy. (Phys.org)

The study has been reported in Science Advances.

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