Detrimental Increase of Spin-Phonon Coupling in Molecular Qubits on Substrates.

Autor: Mullin KR; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States., Greer RB; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Waters MJ; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States., Amdur MJ; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Sun L; Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States., Freedman DE; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Rondinelli JM; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Jazyk: angličtina
Zdroj: ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2024 Jul 31; Vol. 16 (30), pp. 40160-40169. Date of Electronic Publication: 2024 Jul 17.
DOI: 10.1021/acsami.4c05728
Abstrakt: Molecular qubits are a promising platform for quantum information systems. Although single molecule and ensemble studies have assessed the performance of S = 1/2 molecules, it is understood that to function in devices, regular arrays of addressable qubits supported by a substrate are needed. The substrate imposes mechanical and electronic boundary conditions on the molecule; however, the impact of these effects on spin-lattice relaxation times is not well understood. Here we perform electronic structure calculations to assess the effects of a graphene (C gr ) substrate on the molecular qubit copper phthalocyanine (CuPc). We use a progressive Hessian approach to efficiently calculate and separate the substrate contributions. We also use a simple thermal model to predict the impact of these changes on the spin-phonon coupling from 0 to 200 K. Further analysis of the individual vibrational modes with and without C gr shows that an overall increase in SPC between the vibrations modes of CuPc with the surface reduces the spin-lattice relaxation time T 1 . We explain these changes by examining how the substrate lifts symmetries of CuPc in the absorbed configuration. Our work shows that a surface can have a large unintentional impact on SPC and that ways to reduce this coupling need to be found to fully exploit arrays of molecular qubits in device architectures.
Databáze: MEDLINE
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