Trigonal Bipyramidal V³⁺ Complex as an Optically Addressable Molecular Qubit Candidate.

Area of Science:

• Quantum Information Science
• Synthetic Chemistry
• Materials Science

Background:

• Quantum information science requires reliable quantum bits (qubits) for initialization and readout.
• Integrating molecular systems with optical control mechanisms could advance quantum technologies.

Purpose of the Study:

• To design and characterize a molecular spin qubit with optical addressability.
• To mimic the properties of optically addressable solid-state defects using molecular systems.

Main Methods:

• Synthesis of a spin-triplet vanadium (V³⁺) complex: (C₆F₅)₃trenVCNBu (1).
• Measurement of static spin properties and spin coherence time using electron paramagnetic resonance (EPR) spectroscopy.
• Variable magnetic field photoluminescence (PL) spectroscopy to resolve emission into ground-state spin sublevels.

Main Results:

• Coherent control of the spin qubit was demonstrated using a 240 GHz EPR spectrometer.
• The complex exhibited narrow, near-infrared photoluminescence from a spin-singlet excited state.
• Optical resolution of emission into ground-state spin sublevels was achieved, crucial for spin-selective readout.

Conclusions:

• Trigonally symmetric, heteroleptic V³⁺ complexes show promise as candidates for optically addressable spin qubits.
• This research demonstrates a pathway for using molecular spins in quantum information processing.
• The findings support the integration of molecular qubits into existing quantum infrastructure.