Nuclear quadrupole interaction and zero first-order Zeeman transitions of 167Er3+ in CaWO4

Journal article

We report microwave spectroscopy of ¹⁶⁷Er³⁺ doped in CaWO₄ which reveals the hyperfine splitting of the erbium electronic ground state (Z₁, J_eff=15/2) induced by the I=7/2 nuclear spin. From spectra measured below~50 mK in magnetic fields up to 200 mT, we extract spin Hamiltonian parameters including the electron g, hyperfine A, and nuclear electric quadrupolar Q tensors. Crucially, our analysis demonstrate unambiguously, that the previously unobserved nuclear electric quadrupolar moment is essential to reproduce the experimental data. With these refined parameters, we identify zero first-order Zeeman (ZEFOZ) transitions at zero magnetic field. Extending the analysis to finite fields, we uncover that ZEFOZ points lie either along the c axis or within the a-b plane. These results establish CaWO₄ as a promising host for long lifetime quantum memories.

Authors: Marsh, L; Yikai, Y; Mattiroli, C; Sayat, MT; Trí, ĐM

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B
• Volume: 113
• Issue: 5
• Article number: 54417
• Publication date: 2026-02-11
• Acceptance date: 2026-01-06
• DOI: 10.1103/pg5m-hk2n
• EISSN: 2469-9969
• ISSN: 2469-9950
• Language: English