Einstein-de Haas Nanorotor

TL;DR

This paper introduces a quantum theory for a nanoscale spin-driven rotor between ferromagnetic electrodes, revealing how spin injection can efficiently induce continuous rotation through angular momentum transfer.

Contribution

It develops a quantum model explaining spin-rotation coupling and relaxation processes enabling efficient nanorotor operation under steady current.

Findings

Angular momentum transfer is achieved via spin injection in a ferromagnetic setup.

Relaxation from precession to sleeping top state is key for efficient rotation.

The theory provides a strategy for designing effective nanoscale rotors.

Abstract

We propose a nanoscale rotor embedded between two ferromagnetic electrodes that is driven by spin injection. The spin-rotation coupling allows this nanorotor to continuously receive angular momentum from an injected spin under steady current flow between ferromagnetic electrodes in an antiparallel magnetization configuration. We develop a quantum theory of this angular momentum transfer and show that a relaxation process from a precession state into a sleeping top state is crucial for the efficient driving of the nanorotor by solving the master equation. Our work clarifies a general strategy for efficient driving of a nanorotor.