Encapsulation Enhances the Quantum Coherence of a Solid-State Molecular Spin Qubit.

Area of Science:

• Quantum Information Science
• Supramolecular Chemistry
• Materials Science

Background:

• Molecular spins offer atomistic control for qubit realization.
• Coherent manipulation of spin qubits is possible with electromagnetic radiation.
• Protecting fragile spin qubits in solid-state devices from decoherence is a major challenge.

Purpose of the Study:

• To develop a supramolecular strategy for protecting molecular spin qubits against decoherence.
• To analyze the quantum coherence of an encapsulated qubit compared to an unprotected one.
• To investigate the effect of encapsulation on qubit relaxation times in both solution and solid states.

Main Methods:

• Encapsulation of the [Cr(ox)3]3- molecular qubit within the [Zn2L3]4+ diamagnetic triple-stranded helicate.
• Pulsed Electron Paramagnetic Resonance (EPR) spectroscopy for analyzing quantum coherence.
• Examination of spin-spin and spin-lattice relaxation in solid-state assemblies with varying qubit concentrations.

Main Results:

• Encapsulation of the molecular qubit within the diamagnetic helicate surprisingly increased its phase memory time in the solid state.
• Significant enhancement of spin-lattice relaxation times was observed for the protected qubit in the solid state.
• The free qubit did not exhibit these enhancements in relaxation times.

Conclusions:

• Supramolecular encapsulation provides an effective strategy for protecting molecular spin qubits against decoherence in solid-state environments.
• The enhanced coherence times in the solid state are crucial for advancing the development of molecular quantum computing hardware.
• This approach demonstrates a pathway to robust molecular qubits for solid-state quantum devices.