With atomic designability, fine tunability, and quantum coherence at relatively high temperature, molecular electron spin qubits could enable unprecedented quantum information technologies. Molecular qubit frameworks (MQFs), i.e. crystalline and microporous materials comprising of molecular qubits, offer a versatile platform to engineer phononic, magnetic, and electronic environment surrounding electron spins, enabling precise control of their key qubit metrics including spin relaxation time (T₁) and decoherence time (T₂). Their nanoscale pores further facilitate host-guest interactions, enabling quantum sensing of guest molecules.

In this talk, we will present our recent spin dynamic studies on MQFs. Through pulse electron paramagnetic resonance spectroscopic characterization on a series of MQFs embedding semiquinone radicals, we show that hydrogen-bonded networks and their deuteration facilitate spin relaxation. This finding motivated us to improve T₁ by structural rigidification, synthesizing MQFs with T₁ and T₂ exceeding 300 μs and 5 μs at room temperature, respectively. Analyzing anomalous and tunable spin relaxation in a chiral MQF, we discovered spin-phonon polarons, a new quasiparticle emerging from chirality-induced asymmetric spin-phonon coupling. Finally, we will present quantum sensing of microscopic viscosity and nuclear spins at room temperature in solution with MQFs via relaxometry and hyperfine spectroscopy.

Emergent electron spin dynamics and quantum sensing applications of molecular qubit frameworks

Wenjie Dou

Westlake University

Appearances