Spin-polarized transient electron trapping in phosphorus-doped silicon

Experimental evidence of electron spin precession during travel through the phosphorus-doped Si channel of an all-electrical device simultaneously indicates two distinct processes: (i) short time scales (≈50ps) due to purely conduction-band transport from injector to detector and (ii) long time scales (≈1ns) originating from delays associated with capture or reemission in shallow impurity traps. The origin of this phenomenon, examined via temperature, voltage, and electron density dependence measurements, is established by means of a comparison to a numerical model and is shown to reveal the participation of metastable excited states in the phosphorus-impurity spectrum. This work therefore demonstrates the potential to make the study of macroscopic spin transport relevant to the quantum regime of individual spin interactions with impurities as envisioned for quantum information applications.