Excitonic giant Zeeman effect in GaN:Mn^3+

Wojciech Pacuski (1, 2) , David Ferrand (1) , Joel Cibert (1) , J. A. Gaj (2) , A. Golnik (2) , P. Kossacki (2) , Stéphane Marcet , E. Sarigiannidou , Henri Mariette (1)

1 NEEL - NPSC - Nanophysique et Semiconducteurs
2 IFD - Institute of Experimental Physics [Warsaw]

We describe a direct observation of the excitonic giant Zeeman splitting in (Ga,Mn)N, a wide-gap III-V diluted magnetic semiconductor. Reflectivity and absorption spectra measured at low temperatures display the A and B excitons, with a shift under magnetic field due to s,p-d exchange interactions. Using an excitonic model, we determine the difference of exchange integrals between Mn^3+ and free carriers in GaN, N_0(alpha-beta)=-1.2 +/- 0.2 eV. Assuming a reasonable value of alpha, this implies a positive sign of beta which corresponds to a rarely observed ferromagnetic interaction between the magnetic ions and the holes.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Wojciech Pacuski, David Ferrand, Joel Cibert, J. A. Gaj, A. Golnik, et al.. Excitonic giant Zeeman effect in GaN:Mn^3+. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 76, pp.165304. ⟨10.1103/PhysRevB.76.165304⟩. ⟨hal-00134943⟩