Single electron spin and its coherence in Si quantum computer architecture

TL;DR

This paper evaluates the feasibility of single electron spin measurements in silicon quantum computers, highlighting challenges with electric field requirements and proposing methods for spin-to-charge conversion and coherence measurement.

Contribution

It introduces a new measurement scheme for spin coherence and assesses the practicality of electric field control in Si-based quantum computing.

Findings

Electric fields and tunneling times are likely too large for practical single-spin measurements.

Operations with double donors in excited states require smaller fields and faster tunneling.

Proposes a scheme for statistical estimation of spin coherence at the Si/SiO2 interface.

Abstract

The possibility of performing single spin measurements in Si-based quantum computers through electric field control of electrons bound to double donors near a barrier interface is assessed. We find that both the required electric fields and the tunneling times involved are probably too large for practical implementations. On the other hand, operations with double donors in their first excited state require smaller fields and faster tunneling times, and are therefore suitable for spin-to-charge conversion measurements. We also propose a measurement scheme that would render statistical (ensemble) estimates of the spin coherence at the Si/SiO2 interface.