Nuclear spin dynamics influenced and detected by electron spin polarization in CdTe/CdMgTe quantum wells

TL;DR

This study investigates nuclear spin coherence and dynamics in CdTe/CdMgTe quantum wells by optically detecting nuclear magnetic resonance and analyzing the influence of electron spin polarization on nuclear relaxation.

Contribution

It provides new insights into nuclear spin behavior and coherence times in quantum wells, including measurements of Rabi oscillations and relaxation times for multiple isotopes.

Findings

Measured nuclear Rabi oscillations for isotopes

Determined inhomogeneous dephasing and coherence times

Found weak extension of nuclear relaxation time due to electron spins

Abstract

Nuclear spin coherence and relaxation dynamics of all constituent isotopes of an n-doped CdTe/(Cd,Mg)Te quantum well structure are studied employing optically detected nuclear magnetic resonance. Using time-resolved pump-probe Faraday ellipticity, we generate and detect the coherent spin dynamics of the resident electrons. The photogenerated electron spin polarization is transferred into the nuclear spin system, which becomes polarized and acts back on the electron spins as the Overhauser field. Under the influence of resonant radio frequency pulses, we trace the coherent spin dynamics of the nuclear isotopes $^{111}$Cd, $^{113}$Cd, and $^{125}$Te. We measure nuclear Rabi oscillations, the inhomogeneous dephasing time $T_2^*$, the spin coherence time $T_2$, and the longitudinal relaxation time $T_1$. Furthermore, we investigate the influence of the laser excitation and the corresponding electron spin polarization on the nuclear spin relaxation time and find a weak extension of this time induced by interaction with the electron spins.