Resonant harmonic generation and collective spin rotations in electrically driven quantum dots

TL;DR

This paper investigates how AC electric fields induce spin rotations in double quantum dots, revealing resonant harmonic generation and fractional resonances driven by interdot tunnel coupling, with implications for quantum control.

Contribution

It provides an exact numerical analysis showing the universal mechanism of harmonic generation and fractional resonances in electrically driven quantum dot systems, independent of electron interactions.

Findings

Resonance line splitting by spin exchange coupling.

Appearance of fractional resonances due to interdot tunneling.

Amplification of harmonics at the main transition frequency.

Abstract

Spin rotations induced by an AC electric field in a two-electron double quantum dot are studied by an exact numerical solution of the time dependent Schroedinger equation in the context of recent electric dipole spin resonance experiments based on the Pauli blockade. We demonstrate that the splitting of the main resonance line by the spin exchange coupling is accompanied by the appearance of fractional resonances and that both these effects are triggered by interdot tunnel coupling. We find that the AC driven system generates residual but distinct harmonics of the driving frequency which are amplified when tuned to the main transition frequency. The mechanism is universal for electron systems in electrically driven potentials and works also in the absence of electron-electron interaction or spin-orbit coupling.