Hyperfine interaction mediated electric-dipole spin resonance: the role of frequency modulation

TL;DR

This paper investigates how frequency modulation enhances hyperfine-mediated electric-dipole spin resonance in quantum dots, significantly increasing spin-flip efficiency from 20% to 70%.

Contribution

It demonstrates the crucial role of frequency modulation in improving hyperfine-mediated EDSR, revealing a lower bound on modulation amplitude related to hyperfine field fluctuations.

Findings

Frequency modulation increases spin-flip probability from 20% to 70%.

A lower bound on modulation amplitude is linked to hyperfine field width.

FM is essential for effective hyperfine-mediated EDSR.

Abstract

The electron spin in a semiconductor quantum dot can be coherently controlled by an external electric field, an effect called electric-dipole spin resonance (EDSR). Several mechanisms can give rise to the EDSR effect, among which there is a hyperfine mechanism, where the spin-electric coupling is mediated by the electron-nucleus hyperfine interaction. Here, we investigate the influence of frequency modulation (FM) on the spin-flip efficiency. Our results reveal that FM plays an important role in the hyperfine mechanism. Without FM, the electric field almost cannot flip the electron spin; the spin-flip probability is only about 20%. While under FM, the spin-flip probability can be improved to approximately 70%. In particular, we find that the modulation amplitude has a lower bound, which is related to the width of the fluctuated hyperfine field.