Scrambling and Gate Effects in Realistic Quantum Dots

TL;DR

This paper investigates the magnitude of scrambling and gate effects in realistic quantum dots using self-consistent and approximate models, finding small scrambling effects but notable gate-induced spin transitions.

Contribution

It systematically compares scrambling and gate effects in quantum dots using both Kohn-Sham and Strutinsky approaches, highlighting the dominance of residual interactions.

Findings

Genuine scrambling effect is small due to smooth potential.

Residual interactions in KS theory make scrambling appear larger.

Gate effect can induce spin transitions despite being small.

Abstract

We evaluate the magnitude of two important mesoscopic effects using a realistic model of typical quantum dots. ``Scrambling'' and ``gate effect'' are defined as the change in the single-particle spectrum due to added electrons or gate-induced shape deformation, respectively. These two effects are investigated systematically in both the self-consistent Kohn-Sham (KS) theory and a Fermi liquid-like Strutinsky approach. We find that the genuine scrambling effect is small because the potential here is smooth. In the KS theory, a key point is the implicit inclusion of residual interactions in the spectrum; these dominate and make scrambling appear larger. Finally, the gate effect is comparable in the two cases and, while small, is able to cause gate-induced spin transitions.