Strain-induced quantum ring hole states in a gated vertical quantum dot

TL;DR

This paper reports the experimental observation of hole states in a strained Si/SiGe quantum dot that form a quantum ring due to inhomogeneous strain, revealing unique magnetic properties and suggesting new fabrication methods.

Contribution

It demonstrates the formation of quantum ring hole states in a gated vertical quantum dot caused by strain relaxation, providing new insights into quantum ring structures.

Findings

Magnetotunneling spectroscopy shows periodic energy states in /.

Energy shifts are larger than simple ring theory predictions.

Strain relaxation creates a ring-like potential confining hole states.

Abstract

We have experimentally investigated the hole states in a gated vertical strained Si/SiGe quantum dot. We demonstrate the inhomogeneous strain relaxation on the lateral surface creates a ring-like potential near the perimeter of the dot, which can confine hole states exhibiting quantum ring characteristics. The magnetotunneling spectroscopy exhibits the predicted periodicity of energy states in \phi/\phi0, but the magnitude of the energy shifts is larger than predicted by simple ring theory. Our results suggest a new way to fabricate and study quantum ring structures.