High-Symmetry Lanthanide Complexes as Clock-Transition Qubits

Michael Shatruk Florida State University

Qubit is an elementary unit of quantum computing, allowing coherent superposition of states that can be initialized, manipulated, and read-out for quantum information processing. Molecular spin qubits are appealing due to their synthetic tunability and a broad range of spin states that can be incorporated by using various transition and lanthanide metal ions. The generally short coherence time, however, remains the major obstacle for implementation of molecular qubits in quantum computing technology. In this contribution, we demonstrate how this challenge can be addressed by using high-symmetry lanthanide complexes to achieve clock transitions [1,2] characterized by a dramatically enhanced coherence time at specific values of resonant magnetic field. We use variable-frequency EPR spectroscopy to determine the clock-transition energy gaps for the ground- state doublets of crystal-field generated manifolds of ±mJ states and demonstrate the correlations of the gap magnitude to the geometry of the local coordination environment around the lanthanide ion.

[1] M. Shiddiq, D. Komijani, Y. Duan, A. Gaita-Ariño, E. Coronado, S. Hill, Nature 2016, 531, 348-351.

[2] A. Gaita-Ariño, F. Luis, S. Hill, E. Coronado, Nat. Chem. 2019, 11, 301-309.