Anomalously large spin susceptibility enhancement in n-doped CdMnTe quantum wells

Zouhour Ben Cheikh (1) , Steeve Cronenberger (2) , Maria Vladimirova (2) , Denis Scalbert (2) , Kais Boujdaria , Florent Baboux (3) , Florent Perez (3) , Thomas Wojtowicz (4) , Gregorz Karzewski (4)

1 PEPS - Physique de l'Exciton, du Photon et du Spin
2 L2C - Laboratoire Charles Coulomb
3 INSP - Institut des Nanosciences de Paris
4 IFPAN - Institute of Physics [Warsaw]

We report on time-resolved Kerr rotation (TRKR) experiments done on n-doped CdMnTe quantum wells (QWs), in the regime where strong coupling between the electron and the Mn spin-flip excitations shows up. It has been proposed previously to deduce the 2D electron gas spin susceptibility from the coupling energy between these spin excitations. Here we measure the coupling energy on a high mobility sample down to very low excitation density, and compare the results with spin-flip Raman scattering (SFRS) on the same sample. The electron spin polarizations measured by TRKR and SFRS are found in relatively good agreement. However the spin susceptibility measured by TRKR exceeds systematically the values predicted by many-body theory. This could be an indication that the two-oscillator model used to describe mixed electron-Mn spin excitations needs to be improved.

Domaines: Autre [cond-mat.other]

Zouhour Ben Cheikh, Steeve Cronenberger, Maria Vladimirova, Denis Scalbert, Kais Boujdaria, et al.. Anomalously large spin susceptibility enhancement in n-doped CdMnTe quantum wells. ICPS, Jul 2012, Zurich, France. pp.349, ⟨10.1063/1.4848429⟩. ⟨hal-00925573⟩