Tunable Cr4+ molecular color centers

Laorenza, D. W. et al. (2021) Tunable Cr4+ molecular color centers. Journal of the American Chemical Society, 143(50), pp. 21350-21363. (doi: 10.1021/jacs.1c10145)

Abstract

The inherent atomistic precision of synthetic chemistry enables bottom-up structural control over quantum bits, or qubits, for quantum technologies. Tuning paramagnetic molecular qubits that feature optical-spin initialization and readout is a crucial step toward designing bespoke qubits for applications in quantum sensing, networking, and computing. Here, we demonstrate that the electronic structure that enables optical-spin initialization and readout for S = 1, Cr(aryl)4, where aryl = 2,4-dimethylphenyl (1), o-tolyl (2), and 2,3-dimethylphenyl (3), is readily translated into Cr(alkyl)4 compounds, where alkyl = 2,2,2-triphenylethyl (4), (trimethylsilyl)methyl (5), and cyclohexyl (6). The small ground state zero field splitting values (<5 GHz) for 1–6 allowed for coherent spin manipulation at X-band microwave frequency, enabling temperature-, concentration-, and orientation-dependent investigations of the spin dynamics. Electronic absorption and emission spectroscopy confirmed the desired electronic structures for 4–6, which exhibit photoluminescence from 897 to 923 nm, while theoretical calculations elucidated the varied bonding interactions of the aryl and alkyl Cr4+ compounds. The combined experimental and theoretical comparison of Cr(aryl)4 and Cr(alkyl)4 systems illustrates the impact of the ligand field on both the ground state spin structure and excited state manifold, laying the groundwork for the design of structurally precise optically addressable molecular qubits.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bayliss, Dr Sam
• Authors: Laorenza, D. W., Kairalapova, A., Bayliss, S. L., Goldzak, T., Greene, S. M., Weiss, L. R., Deb, P., Mintun, P. J., Collins, K. A., Awschalom, D. D., Berkelbach, T. C., and Freedman, D. E.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Journal of the American Chemical Society
• Publisher: American Chemical Society
• ISSN: 0002-7863
• ISSN (Online): 1520-5126
• Published Online: 24 November 2021
• Copyright Holders: Copyright © 2021 American Chemical Society
• First Published: First published in Journal of the American Chemical Society 143(50):21350-21363
• Publisher Policy: Reproduced in accordance with the publisher copyright policy