Goldstone mode relaxation in a quantum hall ferromagnet due to hyperfine interaction with nuclei
S. Dickmann
Institute for Solid State Physics of RAS, 142432 Chernogolovka, Moscow District, Russia
Abstract
Spin relaxation in quantum Hall ferromagnet regimes
is studied. As the initial non-equilibrium state, a coherent
deviation of the spin system from the direction is
considered and the breakdown of this Goldstone-mode state due
to hyperfine coupling to nuclei is analyzed. The relaxation
occurring non-exponentially with time is studied in terms of
annihilation processes in the "Goldstone condensate" formed by
"zero spin excitons". The relaxation rate is
calculated analytically even if the initial deviation is not small.
This relaxation channel competes with the relaxation mechanisms due to
spin-orbit coupling, and at strong magnetic fields it becomes
dominating.