Quantum advantage in a molecular spintronic engine that harvests thermal fluctuation energy

TL;DR

This paper proposes a molecular spintronic quantum engine that autonomously harvests thermal fluctuation energy, demonstrating quantum advantages with high efficiency and spin polarization, potentially advancing clean energy technologies.

Contribution

It introduces a novel, autonomous molecular spintronic quantum engine utilizing spin coherence and electron spin selection, surpassing classical limits without external electromagnetic drives.

Findings

Achieved stable dc current generation in molecular devices

Demonstrated output power above room temperature

Recorded 89% spin polarization of current

Abstract

Recent theory and experiments have showcased how to harness quantum mechanics to assemble heat/information engines with efficiencies that surpass the classical Carnot limit. So far, this has required atomic engines that are driven by cumbersome external electromagnetic sources. Here, using molecular spintronics, we propose an implementation that is both electronic and autonomous. Our spintronic quantum engine heuristically deploys several known quantum assets by having a chain of spin qubits formed by the paramagnetic Co centers of phthalocyanine (Pc) molecules electronically interact with electron-spin selecting Fe/C60 interfaces. Density functional calculations reveal that transport fluctuations across the interface can stabilize spin coherence on the Co paramagnetic centers, which host spin flip processes. Across vertical molecular nanodevices, we measure enduring dc current generation, output power above room temperature, two quantum thermodynamical signatures of the engine's processes, and a record 89% spin polarization of current across the Fe/C60 interface. It is crucially this electron spin selection that forces, through demonic feedback and control, charge current to flow against the built-in potential barrier. Further research into spintronic quantum engines, insight into the quantum information processes within spintronic technologies, and retooling the spintronic-based information technology chain, could help accelerate the transition to clean energy.