Dynamic Decoupling Doubles Coherence Times in a Nuclear Spin "Lite" Vanadium(IV) Tris(dithiolate).

Area of Science:

• Quantum Information Science
• Molecular Magnetism
• Spin Dynamics

Background:

• Transition-metal complexes are promising for quantum applications due to their spin properties.
• Maintaining spin coherence is crucial for quantum information processing but is often limited by environmental interactions.
• Deuterated solvents and dynamic decoupling are strategies to improve spin coherence times.

Purpose of the Study:

• To investigate the spin dynamics of a specific vanadium complex, (AsPh4-d20)2[V(mnt)3], in a deuterated solvent system.
• To achieve and characterize long coherence times for a transition-metal-based spin.
• To evaluate the effectiveness of dynamic decoupling pulse sequences in extending coherence times.

Main Methods:

• Utilized a tris(dithiolate)vanadium complex dianion with a perdeuterotetraphenylarsonium cation.
• Performed experiments in a CDCl3/Cl3CCN (4:1) solvent system.
• Applied Carr-Purcell and Uhrig-type dynamic decoupling pulse sequences.

Main Results:

• Achieved the longest reported coherence times (T1 = 164(4) ms, TM = 60(2) μs) for a transition-metal spin in deuterated solvents.
• Dynamic decoupling more than doubled the TM, reaching 136(13) μs.
• Identified a fast decoherence process (50-85%) significantly limiting the effectiveness of extended pulse sequences.

Conclusions:

• The study demonstrates significant progress in extending spin coherence times for transition-metal complexes.
• Limited effectiveness of current dynamic decoupling highlights the need for a completely purged electron-spin environment.
• Future research should combine dynamic decoupling with electron-spin environment engineering to overcome fast decoherence.