Optically addressable molecular spins for quantum information processing

Abstract

Spin-bearing molecules are promising building blocks for quantum technologies as they can be chemically tuned, assembled into scalable arrays, and readily incorporated into diverse device architectures. In molecular systems, optically addressing ground-state spins would enable a wide range of applications in quantum information science, as has been demonstrated for solid-state defects. However, this important functionality has remained elusive for molecules. Here, we demonstrate such optical addressability in a series of synthesized organometallic, chromium(IV) molecules. These compounds display a ground-state spin that can be initialized and read out using light, and coherently manipulated with microwaves. In addition, through atomistic modification of the molecular structure, we vary the spin and optical properties of these compounds, indicating promise for designer quantum systems synthesized from the bottom-up.

Quantum Engineering With Hybrid Magnonic Systems and Materials (Invited Paper)

“…Further afield, qubits consisting of organic molecules containing transition metal ions have recently shown very promising spin and optical properties that can be tuned with ligand chemistry. 274 Coupling such qubits with low-damping organic magnets like V [TCNE] x could enable all-organic quantum spintronics with qubits separated from magnon waveguides by atomic-scale distances with facile deposition and chemical tunability. Overcoming material and fabrication challenges both in more traditional systems (e.g., YIG, diamond) and emerging materials is a key priority in the development of integrated magnon/spin-qubit hybrid technologies.…”

A Molecular Approach to Quantum Sensing

“…To address these challenges, we and others are employing coordination chemistry to rationally control both the physical and electronic structure as well as coherence properties including quantum state lifetimes ( T 1 ) and coherence times ( T m ). 25 , 31 , 64 − 92 Ligand design provides an immediate route to achieve long T 1 and T m or optical initialization and read-out pathways. Further tuning parameters such as spin–orbit coupling, crystal field splitting, and electron–nuclear hyperfine interaction provide additional handles to optimize the requisite sensor criteria mentioned above.…”

“…We recently demonstrated all optical initialization and read-out with three spin-triplet molecular systems, a first important step toward this goal. 31 …”

Pseudo-Tetrahedral vs Pseudo-Octahedral ErIII Single Molecule Magnets and the 'Disruptive' Role of Coordinated TEMPO Radicals

“…The design of lanthanide-based single molecule magnets (Ln-SMMs) 1 with the overarching goal of controlling and finetuning their magnetic properties is currently one of the hottest topics in the rapidly developing field of multifunctional molecule-based magnetic materials. 2,3 This is due to the very high interest in manufacturing reliable single-molecule components for quantum information processing (QIP) applications 4,5 showing quantum phase interference, 6 quantum entanglement of the magnetic states, 7 coherent spin manipulation 8,9 and clock transitions 10 as well as potential hightemperature single-molecule magnetic memory devices. 11 One of the most challenging goals in this vein is the precise design and control of appropriate ligand-scafflods, 12 including the number of donor atoms, their position and symmetry, and the ligand field strength, 13 so that the target SMMs can perform in a completely predictable manner at the highest possible temperature.…”