Tristan Clua Provost - Quantum Science and Engineering Seminar

The Negatively Charged Boron Vacancy Center In Hexagonal Boron Nitride: Toward An Atomically Thin Quantum Sensor

Tristan Clua Provost I University of Montpellier

Combining high sensitivity with micro- to nanoscale spatial resolution, quantum sensors based on solid-state spin defects have attracted growing interest across a wide range of disciplines. In this seminar, Provost will present his PhD work on an alternative route toward atomic-scale proximity: optically active spin defects embedded in van der Waals (vdW) materials. He will focus on negatively charged boron-vacancy (VB) centers in hexagonal boron nitride (hBN), by first showing that these defects exhibit spin-dependent photodynamics similar to those of nitrogen-vacancy centers in diamond, enabling magnetic-field sensing through optically detected magnetic resonance. As a proof of principle, Provost will present magnetic imaging of a van der Waals magnet using an 80-nm-thick hBN sensing flake. Having established centers as magnetic-field sensors, he will then show that these defects retain their spin-dependent optical properties in few-layer hBN, with isotopic purification further improving their magnetic-field sensitivity.

Finally, Provost will discuss the impact of an atomic-scale thickness on the spin relaxation times of VB centers. While the longitudinal spin relaxation time is degraded in ultrathin hBN flakes, we observe that spin coherence is surprisingly preserved and can be extended to the microsecond timescale using dynamical decoupling. These results establish VB centers in hBN as a compelling platform for quantum sensing, opening perspectives for applications that require placing the sensor in immediate proximity to the sample, such as nanoscale nuclear magnetic resonance spectroscopy."

For more information:

David Awschalom: awsch@uchicago.edu
Peter Maurer: pmaurer@uchicago.edu
Chicago Quantum Institute: qi@uchicago.edu