Chemical tuning of spin clock transitions in molecular monomers based on nuclear spin-free Ni(<scp>ii</scp>)

Rubín-Osanz, Marcos; Lambert, François; Shao, Feng; Rivière, Éric; Guillot, Régis; Suaud, Nicolas; Guihéry, Nathalie; Zueco, David; Barra, Anne‐Laure; Mallah, Talal; Luìs, Fernando

doi:10.1039/d0sc05856d

Cited by 21 publications

(19 citation statements)

References 53 publications

(107 reference statements)

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“…While the sign of the D parameter was not determined in the experimental studies, 25,26 it can be unambiguously obtained by specific heat measurements as a function of temperature. 43 For the M1 molecule, the magnetic easy axis is found to be along the S 4 symmetry axis.…”

Section: Spin-orbit Coupling Effect I: Zero-field Splittingmentioning

confidence: 95%

Computational Insights into Electronic Excitations, Spin-Orbit Coupling Effects, and Spin Decoherence in Cr(IV)-based Molecular Qubits

Janicka¹,

Wysocki²,

Park³

2022

Preprint

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The great success of point defects and dopants in semiconductors for quantum information processing has invigorated a search for molecules with analogous properties.Flexibility and tunability of desired properties in a large chemical space have great advantages over solid-state systems. The properties analogous to point defects were demonstrated in Cr(IV)-based molecular family, Cr(IV)(aryl) 4 , where the electronic spin states were optically initialized, read out, and controlled. Despite this kick-start, there is still a large room for enhancing properties crucial for molecular qubits. Here we provide computational insights into key properties of the Cr(IV)-based molecules aimed at assisting chemical design of efficient molecular qubits. Using the multireference ab-initio methods, we investigate the electronic states of Cr(IV)(aryl) 4 molecules with slightly different ligands, showing that the zero-phonon line energies agree with the experiment, and that the excited spin-triplet and spin-singlet states are highly sensitive to small chemical perturbations. By adding spin-orbit interaction, we find that the

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Section: Spin-orbit Coupling Effect I: Zero-field Splittingmentioning

confidence: 95%

Computational Insights into Electronic Excitations, Spin-Orbit Coupling Effects, and Spin Decoherence in Cr(IV)-based Molecular Qubits

Janicka¹,

Wysocki²,

Park³

2022

Preprint

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“…From the experimental point of view, the inverse local spin polarizations on donor and acceptor in the S + 1 , 1/2 and S − 1 , 1/2 states may be of interest for optically controlling the input for all-spin information transfer along spin chains [63][64][65], or to connect and to switch molecular spin qubit candidates [66,67].…”

Section: Acknowledgementsmentioning

confidence: 99%

Exchange Spin Coupling in Optically Excited States

Steenbock

Rybakowski

Benner

et al. 2022

Preprint

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In optically excited states in molecules and materials, coupling between local electron spins plays an important role for their photoemission properties and is interesting for potential applications in quantum information processing. Recently, it was experimentally demonstrated that the photogenerated local spins in donor–acceptor metal complexes can interact with the spin of an attached radical, resulting in a spin-coupling dependent mixing of excited doublet states, which controls the local spin density distributions on donor, acceptor, and radical subunits in optically excited states. In this work, we propose an energy-difference scheme to evaluate spin coupling in optically excited states, using unrestricted and spin-flip simplified time-dependent density functional theory (sTDDFT). We apply it to three platinum complexes which have been studied experimentally to validate our methodology. We find that all computed coupling constants are in excellent agreement with the experimental data. In addition, we show that the spin coupling between donor and acceptor in the optically excited state can be fine-tuned by replacing platinum with palladium and zinc in the structure. Besides the two previously discussed excited doublet states (one bright and one dark), our calculations reveal a third, bright excited doublet state which was not considered previously. This third state possesses the inverse spin polarization on donor and acceptor with respect to the previously studied bright doublet state and is by an order of magnitude brighter, which might be interesting for optically controlling local spin polarizations with potential applications in spin-only information transfer and manipulation of connected qubits.

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“…replacing some of the molecules in the crystal by nonmagnetic derivatives, dissolving them in adequate solvents or reducing the number of nuclear spins) or by encoding the qubit states in "decoherence-free" subspaces formed near level anticrossings. 16,[24][25][26] The application of these methods has led to very significant improvements in spin coherence times T 2 which for some examples are near one ms. 15 Chemical design can also be exploited to expand the available computational space from single qubits to d−dimensional qudits at the level of a microscopic physical object. An option is to create molecular structures hosting several magnetic centres.…”

Section: Scaling Up Within Each Molecule: Molecular Quantum Processorsmentioning

confidence: 99%

A perspective on scaling up quantum computation with molecular spins

Carretta,

Zueco,

Chiesa

et al. 2021

Preprint

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Artificial magnetic molecules can contribute to progressing towards large scale quantum computation by: a) integrating multiple quantum resources and b) reducing the computational costs of some applications. Chemical design, guided by theoretical proposals, allows embedding nontrivial quantum functionalities in each molecular unit, which then acts as a microscopic quantum processor able to encode error protected logical qubits or to implement quantum simulations. Scaling up even further requires "wiring-up" multiple molecules. We discuss how to achieve this goal by the coupling to on-chip superconducting resonators. The potential advantages of this hybrid approach and the challenges that still lay ahead are critically reviewed.

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Chemical tuning of spin clock transitions in molecular monomers based on nuclear spin-free Ni(ii)

Abstract: We report the existence of a sizeable quantum tunnelling splitting between the two lowest electronic spin levels of mononuclear Ni complexes. The level anti-crossing, or magnetic “clock transition”, associated with...

Cited by 21 publications

References 53 publications

Computational Insights into Electronic Excitations, Spin-Orbit Coupling Effects, and Spin Decoherence in Cr(IV)-based Molecular Qubits

Computational Insights into Electronic Excitations, Spin-Orbit Coupling Effects, and Spin Decoherence in Cr(IV)-based Molecular Qubits

Exchange Spin Coupling in Optically Excited States

A perspective on scaling up quantum computation with molecular spins

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