Description
Quantum sensing under extreme conditions offers a powerful route to interrogate materials where conventional probes fail. Extending quantum sensing techniques into the gigapascal pressure regime promises new insight into phase transitions, emergent order, and critical phenomena in correlated materials. To date, most experimental efforts have focused on spin defects in diamond, whose remarkable sensitivity has captured broad interest [1,2]. However, at elevated pressures these defects often suffer from degradation of their quantum coherence and optical addressability, ultimately limiting their performance and applicability in high-pressure environments.
In this talk, I will present a new strategy for quantum sensing at extreme pressures based on optically active spin pairs hosted in hexagonal boron nitride (hBN) [3]. Using a combination of high-pressure spectroscopy and spin-resolved measurements, we demonstrate that the key spin properties of these defects are, to first order, insensitive to applied pressure. Crucially, their optical transitions remain stable and well-defined up to at least 20 GPa, in stark contrast to many existing solid-state quantum sensors [4,5].
Beyond their robustness within the hexagonal phase, we show that these spin defects persist across the structural transition of hBN into the wurtzite phase. This survival across a major crystallographic transformation opens the door to truly in situ quantum sensing through pressure-driven phase transitions. Taken together, these results establish hBN spin pairs as a promising and versatile platform for quantum sensing under extreme conditions, and suggest new opportunities for probing phenomena deep within the high-pressure phase space of quantum materials.
References
[1] Lesik, M. et al. Science 366, 1359–1362 (2019)
[2] Hsieh, S. et al. Science 366, 1349–1354 (2019)
[3] Robertson, I. O. et al. Nat. Phys. 21, 1981–1987 (2025)
[4] Mu, Z. et al. Nat Commun 16, 8574 (2025)
[5] He, G. et al. Nat Commun 16, 8162 (2025)
| I am the presenting author | Yes |
|---|