Electron-Nuclear Spin Polarization Dynamics in InGaAs Quantum Dots.

Dynamics of nuclear spin polarization by optically oriented electrons in an (In, Ga)As/GaAs quantum dot ensemble is studied. At the initial polarization stage, the effective nuclear field rises at rates from units to hundreds of T/s going from weak to strong excitation. When it reaches the strength of a few tens of mT, the further rise is drastically slowed down. [ABSTRACT FROM AUTHOR]