Spin bottleneck in resonant tunneling through double quantum dots with different Zeeman splittings

TL;DR

This paper studies how differing Zeeman splittings in double quantum dots suppress electron tunneling, revealing a spin bottleneck effect that limits current flow even at resonance.

Contribution

It demonstrates the spin bottleneck phenomenon in double quantum dots with different Zeeman splittings and explains how broadening can partially relieve this effect.

Findings

Resonant tunneling is suppressed by spin bottleneck effect.

Maximum current occurs at half the Zeeman energy difference.

Finite broadening alleviates the bottleneck, enhancing current.

Abstract

We investigated the electron transport property of the InGaAs/GaAs double quantum dots, the electron g-factors of which are different from each other. We found that in a magnetic field, the resonant tunneling is suppressed even if one of the Zeeman sublevels is aligned. This is because the other misaligned Zeeman sublevels limit the total current. A finite broadening of the misaligned sublevel partially relieves this bottleneck effect, and the maximum current is reached when interdot detuning is half the Zeeman energy difference.