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Laorenza DW, Kairalapova A, Bayliss SL, Goldzak T, Greene SM, Weiss LR, Deb P, Mintun PJ, Collins KA, Awschalom DD, Berkelbach TC, Freedman DE. Tunable Cr 4+ Molecular Color Centers. J Am Chem Soc 2021; 143:21350-21363. [PMID: 34817994 DOI: 10.1021/jacs.1c10145] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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.
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Affiliation(s)
- Daniel W Laorenza
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Arailym Kairalapova
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sam L Bayliss
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Tamar Goldzak
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Samuel M Greene
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Leah R Weiss
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Pratiti Deb
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.,Department of Physics, University of Chicago, Chicago, Illinois 60637, United States
| | - Peter J Mintun
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Kelsey A Collins
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - David D Awschalom
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.,Department of Physics, University of Chicago, Chicago, Illinois 60637, United States.,Center for Molecular Engineering and Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Timothy C Berkelbach
- Department of Chemistry, Columbia University, New York, New York 10027, United States.,Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
| | - Danna E Freedman
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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