New insights into electron spin dynamics in the presence of correlated noise

TL;DR

This study investigates how correlated noise affects electron spin depolarization in zinc-blende semiconductors, revealing nonmonotonic and field-dependent behaviors that influence spin relaxation lengths.

Contribution

It provides new insights into the impact of correlated noise on spin dynamics, including the effects of noise amplitude, correlation time, and electron-electron interactions.

Findings

Depolarization length shortens with increasing noise at low fields.

Nonmonotonic dependence of spin length on noise correlation time.

External fluctuations can enhance relaxation length at high fields.

Abstract

The changes of the spin depolarization length in zinc-blende semiconductors when an external component of correlated noise is added to a static driving electric field are analyzed for different values of field strength, noise amplitude and correlation time. Electron dynamics is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin depolarization is studied by examinating the decay of the initial spin polarization of the conduction electrons through the D'yakonov-Perel process, the only relevant relaxation mechanism in III-V crystals. Our results show that, for electric field amplitude lower than the Gunn field, the dephasing length shortens with the increasing of the noise intensity. Moreover, a nonmonotonic behavior of spin depolarization length with the noise correlation time is found, characterized by a maximum variation for values of noise correlation time comparable with the dephasing time. Instead, in high field conditions, we find that, critically depending on the noise correlation time, external fluctuations can positively affect the relaxation length. The influence of the inclusion of the electron-electron scattering mechanism is also shown and discussed.