Luminescent Organic Triplet Diradicals as Optically Addressable Molecular Qubits

Area of Science:

• Quantum Information Science
• Organic Chemistry
• Materials Science

Background:

• Solid-state defects like diamond nitrogen vacancy (NV) centers are studied for optical-spin interfaces.
• Molecular qubits offer advantages in synthetic control and scalability for quantum applications.

Purpose of the Study:

• To create and characterize an optical-spin interface in an organic molecular qubit.
• To demonstrate photoinitialization, microwave manipulation, and optical readout of ground state spins in a molecular system.

Main Methods:

• Utilized luminescent tris(2,4,6-trichlorophenyl)methyl (TTM) diradicals connected by a phenyl linker.
• Employed spin-selective excited-state intersystem crossing for photoinitialization.
• Applied fluorescence-detected magnetic resonance spectroscopy for spin readout and coherence time measurements.

Main Results:

• Achieved 80% selectivity in photoinitializing the triplet ground state |T0⟩.
• Demonstrated successful optical readout of ground-state spin after microwave manipulation.
• Measured a polarized ground state lifetime of 45 μs at 85 K, with phase memory times T_m of 5.9 μs (85 K) and 26.8 μs (5 K).

Conclusions:

• Luminescent diradicals with triplet ground states function as optically addressable molecular qubits.
• The demonstrated long spin coherence times are vital for molecular quantum computing.
• This work represents a significant advancement in designing spin-optical interfaces for organic materials.