2026/03/31 by Anonymous, Sahand Tabatabaei, Pritam Priyadarsi +5
Engineering · Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #Geophysics and Sensor Technology #Mechanical and Optical Resonators #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/c994-bzx7
openalex publication_date 2026/06/01 · openalex created_date 2026/06/02 · openalex updated_date 2026/07/28
Quantum sensors based on individual spins provide unprecedented access to local magnetic fields in condensed matter, chemistry, and biology, with solid-state defect spins emerging as the leading platform. However, their molecular-sensing capabilities are limited by confinement to a host lattice, which prevents placement in close proximity to a target molecule. Molecular spins offer an alternative, enabling chemical tunability and flexible positioning relative to the target system. Here we present a nanoscale sensing platform that combines molecular electron spins, ultrasensitive mechanical readout, and Hamiltonian engineering. Using a modified XYXY dipolar decoupling sequence, we suppress electron-electron dipolar interactions across a broad distribution of control fields, extending coherence times to ∼ 400~μs in an attoliter-scale droplet containing ∼100 trityl-OX063 radicals. Leveraging this sequence, we demonstrate frequency-selective detection of nanotesla-scale AC fields and perform sensing and spectroscopy of small, local nuclear-spin ensembles. Collectively, these results establish SQUINT (Spin-based QUantum Integrated Nanomechanical Transduction) as a framework for quantum sensing that affords molecular-level control over sensor properties and enables direct integration into complex molecular targets.