Signature of the Overhauser field on the coherent spin dynamics of donor-bound electron in a single CdTe quantum well

TL;DR

This study investigates how the Overhauser nuclear field influences the coherent spin behavior of donor-bound electrons in a CdTe quantum well, revealing measurable nuclear polarization effects via time-resolved optical methods.

Contribution

It demonstrates the detection and quantification of the Overhauser field in a CdTe quantum well, highlighting its impact on electron spin dynamics and nuclear polarization.

Findings

Measured the Overhauser field reaching up to 9.4 mT.

Found the nuclear polarization to be about 13% of maximum.

Showed the influence of hyperfine interaction on spin coherence.

Abstract

We have studied the coherent spin dynamics in an oblique magnetic field of electrons localized on donors and placed in the middle of a single CdTe quantum well, by using a time-resolved optical technique: the photo-induced Faraday rotation. We showed that this dynamics is affected by a weak Overhauser field created via the hyperfine interaction of optically spin-polarized donor-bound electrons with the surrounding nuclear isotopes carrying non-zero spins. We have measured this nuclear field, which is on the order of a few mT and can reach a maximum experimental value of 9.4 mT. This value represents 13 % of the maximal nuclear polarization, and corresponds also to 13 % of maximal electronic polarization.