Heterogeneous Optically-Detected Spin-Acoustic Resonance in Solid-State Molecular Thin-film

TL;DR

This paper demonstrates room-temperature, mechanically driven spin resonance in a heterogeneously integrated pentacene thin film on a high-Q surface acoustic wave resonator, enabling optically detected, zero-field spin control via acoustic means.

Contribution

It introduces HODSAR, a novel heterogeneously integrated platform for optically detected spin-acoustic resonance at room temperature using a molecular thin film and high-Q SAW resonator.

Findings

Achieved coherent spin manipulation via acoustic driving at zero magnetic field.

Demonstrated spectral selectivity of triplet transitions near 105 MHz.

Observed Rabi oscillations with frequency scaling with RF power.

Abstract

We report an implementation of spin-acoustic resonance in pentacene thin films integrated on a high-quality-factor (high-Q) surface acoustic wave (SAW) resonator on a lithium niobate substrate. Heterogeneous optically detected spin-acoustic resonance (HODSAR) is an optically detected spin-resonance measurement in which the resonant drive is delivered mechanically by a surface acoustic wave (SAW). By leveraging the photo-excited triplet state of pentacene at room temperature, we demonstrate coherent spin manipulation via acoustic driving under zero externally applied magnetic field. The heterogeneously integrated device, referred to as HODSAR, utilizes spin-phonon coupling to achieve mechanically driven, zero-field spin resonance, opening avenues for room-temperature mechanically addressable spin control and device integration. We show that the high-Q multimode response of the SAW resonator enables spectrally selective acoustic addressing of triplet transitions near 105 MHz. Coherent control is evidenced by Rabi oscillations, with a Rabi frequency that increases linearly with the square root of the applied RF input power over the measured drive range, consistent with driven two-level dynamics under acoustic excitation. These results establish spin-acoustic resonance in a heterogeneously integrated molecular thin-film platform and provide a quantitative basis for benchmarking mechanically mediated spin control.