Quenching of magnetization in (III, Mn)V magnetic semiconductor quantum wells under intense laser field assisted by the quasi-two-dimensional electron gas

Abstract

Laser-induced quenching of ferromagnetism in ( III 1 − x , Mn x ) V quantum well magnetic semiconductor is investigated. We propose a mechanism in which an increase of the magnon population of the ferromagnetic sample can be achieved due to the spin-flip electron–magnon scattering of the quasi-two-dimensional electron gas inside the quantum well magnetic semiconductor in the presence of intense laser field. In this case, the laser field imposes a drift velocity to the quasi-two-dimensional electrons so that whenever this drift velocity exceeds the phase velocity of the spin waves, energy from the quasi-two-dimensional electrons gained at the expense of the laser field is transferred to the magnon system thereby increasing the number of magnons (magnon amplification) and as a consequence, a loss of magnetization is obtained. Application for typical ( III 1 − x , Mn x ) V ferromagnetic semiconductor quantum wells such as Ga 1 − x Mn x As / AlAs ( x ∼ 5 % ) provides a reasonable loss of magnetization up to 30 % for laser electric field strengths up to 4 × 10 5 V / cm which is below sample damage threshold field values.