Detection of a large valley-orbit splitting in silicon with two-donor spectroscopy

TL;DR

This paper reports the measurement of a large valley-orbit splitting in silicon phosphorus donors using double dopant transport spectroscopy, closely matching bulk values and surpassing previous nanostructure reports.

Contribution

It demonstrates a precise measurement technique for valley-orbit splitting in silicon nanostructures, aligning experimental results with theoretical simulations.

Findings

Large valley-orbit splitting close to bulk value

Measurement method eliminates environmental artifacts

Results consistent with device geometry

Abstract

We measure a large valley-orbit splitting for shallow isolated phosphorus donors in a silicon gated nanowire. This splitting is close to the bulk value and well above previous reports in silicon nanostructures. It was determined using a double dopant transport spectroscopy which eliminates artifacts induced by the environment. Quantitative simulations taking into account the position of the donors with respect to the Si/SiO$_2$ interface and electric field in the wire show that the values found are consistent with the device geometry.