Direct energy transfer from photocarriers to Mn-ion system in II-VI diluted-magnetic-semiconductor quantum wells

Abstract

The dynamical response of magnetic ion system to pulsed laser excitation is studied in ͑Zn, Mn͒Se/ ͑Zn, Be͒Se and ͑Cd, Mn͒Te/ ͑Cd, Mg͒Te quantum well structures. Contributions of a direct heating of the Mn system by photocarriers and an indirect heating via nonequilibrium phonons are distinguished. Their relative efficiency is measured at different excitation densities and over a wide range of Mn concentrations from 0.4 to 11%. For all studied regimes the direct energy transfer from carriers dominates in ͑Zn,Mn͒Se structures. In ͑Cd,Mn͒Te structures a regime where the direct heating is still prominent but weaker than the phonon contribution is found.

Spin dynamics in semiconductors

“…34) [721,723]. Also, nonequilibrium carrier spin polarization can be transferred to the Mn spin system via exchange interaction [98,724,725] and vice versa [726][727][728][729][730][731]. superlattice can be significantly modified by an external magnetic field [734]: Due to the giant Zeeman splitting, the spindown subband is lowered and the spin-up subband is raised.…”

Ultrafast studies of carrier and magnetization dynamics in GaMnAs

“…⌬ K changes sign with reversal of the external magnetic field and indicates pump-induced demagnetization. This slower demagnetization process is attributed to spin lattice relaxation, [60][61][62][63] in which the excess thermal energy deposited into the lattice by the optically injected carriers leads to heating of the Mn spin system. 3͑a͒ reveals a magnetic field independent contribution to the nonlinear response during the first picosecond.…”

Spin dynamics in semiconductors

“…34) [721,723]. Besides, nonequilibrium carrier spin polarization can be transferred to the Mn spin system via exchange interaction [98,724,725] and vice versa [726][727][728][729][730][731]. Mn spin beats were observed by Crooker et al (see Fig.…”