Solid‐State Quantum Coherence From a High‐Spin Donor–Acceptor Conjugated Polymer

Abstract

AbstractMolecular spin systems that can be chemically tuned, coherently controlled, and readily integrated within devices remain central to the realization of emerging quantum technologies. Organic high‐spin materials are prime candidates owing to their similarity in electronic structure to leading solid‐state defect‐based systems, light element composition, and the potential for entanglement and qubit operations mediated through spin‐spin exchange. However, the inherent instability of these species precludes their rational design, development, and application. Here, the first example of an organic high‐spin qubit based on a conjugated polymer semiconductor comprised of alternating dithienosilole and thiadiazoloquinoxaline heterocycles is demonstrated. It is shown that electron spins within the macromolecule demonstrate high‐fidelity coherent control of the superposition state with room temperature coherence and solid‐state relaxation times that are competitive with or exceed other synthetic molecular qubits. These attributes, along with robust stability, chemical tunability, rich interrelated optoelectronic functionalities, and solution processability, offer a fundamentally new approach to integrating quantum phenomena within functional device platforms.