Heating of the Mn spin system by photoexcited holes in type‐II (Zn,Mn)Se/(Be,Mn)Te quantum wells

Abstract

The efficiency of the Mn‐spin system heating under pulsed laser excitation is studied in diluted magnetic semiconductor heterostructures Zn0.99 Mn0.01 Se/Be0.93 Mn0.07 Te with type‐II band alignment by means of time‐resolved photoluminescence and pump‐probe reflectivity. An essential role in the heating is played by multiple spin‐flip scatterings of a hole with localized spins of Mn2+ ions. The efficiency of the spin and energy transfer from photoexcited holes to Mn ions of the Zn0.99 Mn0.01 Se layer considerably depends on the hole lifetime in this layer. This lifetime can be limited by the hole relaxation into the Be0.93 Mn0.07 Te layers and is strongly sensitive to the excitation power and Zn0.99 Mn0.01 Se layer thickness. These dependences allow us to determine a characteristic time of about 20ps for the spin and energy transfer from photoexcited holes to the Mn spin system.

Influence of nonmagnetic impurity scattering on spin dynamics in diluted magnetic semiconductors

“…For this purpose, spintronic devices based on semiconductors are preferable to metallic structures since the dephasing time in a metal is about three orders of magnitude shorter than in a semiconductor 4 . In the context of semiconductor spintronics [5][6][7] , a particularly interesting class of materials for future applications are diluted magnetic semiconductors (DMS) [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] , which are obtained when semiconductors are doped with transition metal elements, such as Mn, which act as localized magnetic moments. While some types of DMS, such as Ga 1−x Mn x As, exhibit a ferromagnetic phase 8,23 , other types of DMS, like the usually paramagnetic CdMnTe, are especially valued for the enhancement of the effective carrier g-factor by the giant Zeeman effect that can be used, e.g., to facilitate an injection of a spin-polarized current into a light-emitting diode 24 .…”