Physical mechanisms of interface-mediated intervalley coupling in Si

TL;DR

This paper investigates how interface properties in silicon affect valley splitting, which is crucial for quantum computing, providing theoretical criteria for optimizing fabrication to enhance qubit performance.

Contribution

It offers a theoretical framework linking interface characteristics to valley splitting, guiding fabrication for improved silicon-based quantum devices.

Findings

Interface abruptness influences valley splitting

Certain interface properties can be optimized to maximize splitting

Theoretical criteria for fabrication parameters are proposed

Abstract

The conduction band degeneracy in Si is detrimental to quantum computing based on spin qubits, for which a nondegenerate ground orbital state is desirable. This degeneracy is lifted at an interface with an insulator as the spatially abrupt change in the conduction band minimum leads to intervalley scattering. We present a theoretical study of the interface-induced valley splitting in Si that provides simple criteria for optimal fabrication parameters to maximize this splitting. Our work emphasizes the relevance of different interface-related properties to the valley splitting.