Optical vortex driven charge current loop and optomagnetism in fullerenes

TL;DR

This paper predicts that weak light vortex pulses can induce controllable charge current loops and magnetic fields in fullerenes, enabling ultrafast local magnetization control for molecular electronics.

Contribution

First ab-initio prediction of light vortex pulses generating charge current loops and magnetic fields in fullerenes for magnetization control.

Findings

Ultraviolet vortex femtosecond pulses induce nA surface currents.

Generated magnetic fields reach hundreds of microtesla.

Charge current control depends on light frequency, topological charge, and intensity.

Abstract

Endohedral molecular magnets, e.g. as realized in fullerenes containing $\rm DySc_{2}N$, are promising candidates for molecular electronics and quantum information processing. For their functionalization an ultrafast local magnetization control is essential. Using full ab-initio quantum chemistry calculations we predict the emergence of charge current loops in fullerenes with an associated orbital magnetic moment upon irradiation with weak light vortex pulses that transfer orbital angular momentum. The generated current is controllable by the frequency, the vortex topological charge, and the intensity of the light. Numerical and analytical results show that an ultraviolet vortex femtosecond pulse with an intensity $\sim10^{13}$ W/cm$^2$ generates non-invasively nA unidirectional surface current with an associated magnetic field of hundreds $\mu$T at the center of the fullerene.