Twenty-three millisecond electron spin coherence of erbium ions in a natural-abundance crystal

Marianne Le Dantec (1, 2) , Miloš Rančić (1, 2) , Sen Lin (3, 4) , Eric Billaud (1, 2) , Vishal Ranjan (1, 2) , Daniel Flanigan (1, 2) , Sylvain Bertaina (5) , Thierry Chanelière (6) , Philippe Goldner (7) , Andreas Erb (8) , Ren Bao Liu (3, 4) , Daniel Estève (1, 2) , Denis Vion (1, 2) , Emmanuel Flurin (1, 2) , Patrice Bertet (1, 2)

1 SPEC - UMR3680 - Service de physique de l'état condensé
2 QUANTRONICS - Quantronics Group
3 CUHK - The Chinese University of Hong Kong [Hong Kong]
4 Department of Physics [Hong Kong University of Science and Technology]
5 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
6 NEEL - NPSC - Nanophysique et Semiconducteurs
7 IRCP - Institut de Recherche de Chimie Paris
8 BADW - Bayerische Akademie der Wissenschaften

Erbium ions doped into crystals have unique properties for quantum information processing, because of their optical transition at 1.5 $\mu$m and of the large magnetic moment of their effective spin-1/2 electronic ground state. Most applications of erbium require however long electron spin coherence times, and this has so far been missing. Here, by selecting a host matrix with a low nuclear-spin density (CaWO$_4$) and by quenching the spectral diffusion due to residual paramagnetic impurities at millikelvin temperatures, we obtain an Er$^{3+}$ electron spin coherence time of 23 ms. This is the longest electron spin coherence time measured in a material with a natural abundance of nuclear spins and on a magnetically-sensitive transition. Our results establish Er$^{3+}$:CaWO$_4$ as a leading platform for quantum networks.

Domaines: Physique Quantique [quant-ph]

Marianne Le Dantec, Miloš Rančić, Sen Lin, Eric Billaud, Vishal Ranjan, et al.. Twenty-three millisecond electron spin coherence of erbium ions in a natural-abundance crystal. Science Advances , 2021, 7 (51), pp.abj9786. ⟨10.1126/sciadv.abj9786⟩. ⟨hal-03366785⟩