Quantum Interference Controls the Electron Spin Dynamics in n-GaAs

Physical Review X. 2018. Vol. 8. P. 031021-1–031021-8.

Belykh V. V., Kuntsevich A., Glazov M. M., Kavokin K. V., Yakovlev D. R., Bayer M.

Manifestations of quantum interference effects in macroscopic objects are rare. Weak localization is one
of the few examples of such effects showing up in the electron transport through solid state. Here, we show
that weak localization becomes prominent also in optical spectroscopy via detection of the electron spin
dynamics. In particular, we find that weak localization controls the free electron spin relaxation in
semiconductors at low temperatures and weak magnetic fields by slowing it down by almost a factor of two
in n-doped GaAs in the metallic phase. The weak localization effect on the spin relaxation is suppressed by
moderate magnetic fields of approximately 1 T, which destroy the interference of electron trajectories, and
by increasing the temperature. The weak localization suppression causes an anomalous decrease of the
longitudinal electron spin relaxation time T1 with magnetic field, in stark contrast with the well-known
magnetic-field-induced increase in T1. This is consistent with transport measurements, which show the
same variation of resistivity with magnetic field. Our discovery opens up a vast playground to explore
quantum magnetotransport effects optically in the spin dynamics.

Keywords: semiconductors, полупроводники, переход металл-изолятор, Metal-insulator transition, spin dynamics, weak localization, спиновая динамика, слабая локализация

Publication based on the results of: Developments in condensed-matter physics (2018)