Spin-lattice relaxation in semimagnetic CdMnTe/CdMgZnTe quantum wells witha two-dimensional hole gas tuned by optical excitation

We measure the spin-lattice relaxation time of Mn ions in Cd1-xMnxTe/Cd(0.6 6)Mg0(.27)Zn(0.07)Te (x = 0.0035) semimagnetic quantum wells in the presenc e of a two-dimensional hole gas (2DHG) with sheet densities up to 3 X 10(10 ) cm(-2). We show that the presence of a 2DHG reduces the spin-lattice rela xation time by more than one order of magnitude. This reduction is much str onger than a similar effect induced by the presence of a two-dimensional el ectron gas, which is due to the heavier hole mass and stronger p-d interact ion for holes with Mn ions. We demonstrate experimentally the possibility t o tune the spin-lattice relaxation time by varying the density of the 2DHG through above-barrier photoexcitation. (C) 2001 Elsevier Science Ltd. All r ights reserved.