Molecular Diradical Spin Qubits in a Crystalline Host as a Platform for Quantum Sensing

Area of Science:

• Materials Science
• Quantum Physics
• Spectroscopy

Background:

• Molecular color centers are crucial for quantum technologies.
• Tris-(2,4,6-trichlorophenyl)-methyl diradical (TTM)₂ exhibits unique optical-spin properties.
• Host crystals like diamagnetic precursor m (HTTM)₂ can host dopant molecules.

Purpose of the Study:

• To create a molecular color center with enhanced optical-spin interface properties.
• To investigate coherent spin control and optical polarization of TTM₂ within an HTTM₂ host.
• To explore the potential for quantum sensing applications.

Main Methods:

• Doping luminescent TTM₂ into HTTM₂ host crystals.
• Optical polarization via spin-selective intersystem crossing.
• Pulsed optically detected magnetic resonance (ODMR) spectroscopy.

Main Results:

• Achieved optical polarization of the TTM₂ triplet ground state sublevel.
• Demonstrated a 10-fold improvement in ODMR contrast using pulsed ODMR.
• Observed spin coherence times up to 7.4 μs at 5 K.
• Photoluminescence is sensitive to weak magnetic fields, independent of external conditions.

Conclusions:

• The TTM₂-doped HTTM₂ system forms a promising molecular color center for quantum sensing.
• Coherent spin control and enhanced ODMR contrast were achieved.
• The material demonstrates potential for robust ambient quantum sensing of anisotropic magnetic fields.