Tunable high speed atomic rotor in Bi$_{2}$Se$_{3}$ revealed by current noise

TL;DR

This paper reports the discovery of a tunable atomic rotor embedded in Bi$_{2}$Se$_{3}$, driven by current, with high switching speeds, enabling potential applications in nanoscale machinery and quantum devices.

Contribution

It demonstrates controlled manipulation of an atomic rotor within a topological insulator host, revealing high-speed switching driven by current and detailed fluctuation analysis.

Findings

Switching rates of hundreds of kHz achieved

Current-driven omni-directional switching between three states

Rotor can be frozen at small bias voltages

Abstract

The ability to manipulate individual atoms and molecules using a scanning tunnelling microscope (STM) has been crucial for the development of a vast array of atomic scale devices and structures ranging from nanoscale motors and switches to quantum corrals. Molecular motors in particular have attracted considerable attention in view of their potential for assembly into complex nanoscale machines. Whereas the manipulated atoms or molecules are usually on top of a substrate, motors embedded in a lattice can be very beneficial for bottom-up construction, and may additionally be used to probe the in uence of the lattice on the electronic properties of the host material. Here, we present the discovery of controlled manipulation of a rotor in Fe doped Bi$_{2}$Se$_{3}$. We find that the current into the rotor, which can be finely tuned with the voltage, drives omni-directional switching between three equivalent orientations, each of which can be frozen in at small bias voltage. Using current fluctuation measurements at 1MHz and model simulations, we estimate that switching rates of hundreds of kHz for sub-nA currents are achieved.