TY - JOUR

T1 - Electron charge and spin delocalization revealed in the optically probed longitudinal and transverse spin dynamics in n -GaAs

AU - Belykh, Vasilii

AU - Kavokin, K. V.

AU - Yakovlev, D. R.

AU - Bayer, M.

PY - 2017/12/7

Y1 - 2017/12/7

N2 - The evolution of the electron spin dynamics as consequence of carrier delocalization in n-type GaAs is investigated by the recently developed extended pump-probe Kerr/Faraday rotation spectroscopy. We find that isolated electrons localized on donors demonstrate a prominent difference between the longitudinal and transverse spin relaxation rates in a magnetic field, which is almost absent in the metallic phase. The inhomogeneous transverse dephasing time T2∗ of the spin ensemble strongly increases upon electron delocalization as a result of motional narrowing that can be induced by increasing either the donor concentration or the temperature. An unexpected relation between T2∗ and the longitudinal spin relaxation time T1 is found, namely, that their product is about constant, as explained by the magnetic field effect on the spin diffusion. We observe a two-stage longitudinal spin relaxation, which suggests the establishment of spin temperature in the system of exchange-coupled donor-bound electrons.

AB - The evolution of the electron spin dynamics as consequence of carrier delocalization in n-type GaAs is investigated by the recently developed extended pump-probe Kerr/Faraday rotation spectroscopy. We find that isolated electrons localized on donors demonstrate a prominent difference between the longitudinal and transverse spin relaxation rates in a magnetic field, which is almost absent in the metallic phase. The inhomogeneous transverse dephasing time T2∗ of the spin ensemble strongly increases upon electron delocalization as a result of motional narrowing that can be induced by increasing either the donor concentration or the temperature. An unexpected relation between T2∗ and the longitudinal spin relaxation time T1 is found, namely, that their product is about constant, as explained by the magnetic field effect on the spin diffusion. We observe a two-stage longitudinal spin relaxation, which suggests the establishment of spin temperature in the system of exchange-coupled donor-bound electrons.

UR - http://www.scopus.com/inward/record.url?scp=85039425629&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.96.241201

DO - 10.1103/PhysRevB.96.241201

M3 - Article

AN - SCOPUS:85039425629

VL - 96

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 24

M1 - 241201

ER -