Disorder-induced valley-orbit hybrid states in Si quantum dots

TL;DR

This paper introduces a new effective mass theory to analyze how disorder affects valley-orbit coupling in silicon quantum dots, revealing hybridization effects that impact quantum information storage.

Contribution

It presents a systematic theoretical framework for understanding valley-orbit interactions in disordered silicon quantum dots, highlighting effects detrimental to quantum information applications.

Findings

Valley-orbit hybridization causes non-zero dipole matrix elements.

Disorder alters intervalley tunneling.

Hybrid states impact quantum information stability.

Abstract

Quantum dots in silicon are promising candidates for implementation of solid-state quantum information processing. It is important to understand the effects of the multiple conduction band valleys of silicon on the properties of these devices. Here we introduce a novel, systematic effective mass theory of valley-orbit coupling in disordered silicon systems. This theory reveals valley-orbit hybridization effects that are detrimental for storing quantum information in the valley degree of freedom, including non-vanishing dipole matrix elements between valley states and altered intervalley tunneling.