Coherent spin transport through a 350-micron-thick Silicon wafer

TL;DR

This study demonstrates the successful all-electrical injection, transport, and detection of spin-polarized electrons through a 350-micron-thick silicon wafer, revealing high spin coherence and a long spin lifetime.

Contribution

It presents the first measurement of coherent spin transport through such a thick silicon wafer using all-electrical methods, with detailed analysis of spin precession and lifetime.

Findings

Spin coherence with at least 13pi precession angles

Transit time correlates with magnetocurrent changes

Spin lifetime (T1) exceeds 500ns at 60K

Abstract

We use all-electrical methods to inject, transport, and detect spin-polarized electrons vertically through a 350-micron-thick undoped single-crystal silicon wafer. Spin precession measurements in a perpendicular magnetic field at different accelerating electric fields reveal high spin coherence with at least 13pi precession angles. The magnetic-field spacing of precession extrema are used to determine the injector-to-detector electron transit time. These transit time values are associated with output magnetocurrent changes (from in-plane spin-valve measurements), which are proportional to final spin polarization. Fitting the results to a simple exponential spin-decay model yields a conduction electron spin lifetime (T1) lower bound in silicon of over 500ns at 60K.