Anti-crossings of spin-split Landau levels in an InAs two-dimensional   electron gas with spin-orbit coupling
  We report tilted-field transport measurements in the quantum-Hall regime in an InAs/In_0.75Ga_0.25As/In_0.75Al_0.25As quantum well. We observe anti-crossings of spin-split Landau levels, which suggest a mixing of spin states at Landau level coincidence. We propose that the level repulsion is due to the presence of spin-orbit and of band-non-parabolicity terms which are relevant in narrow-gap systems. Furthermore, electron-electron interaction is significant in our structure, as demonstrated by the large values of the interaction-induced enhancement of the electronic g-factor. 
W. Desrat, F. Giazotto, V. Pellegrini, M. Governale, F. Beltram, F.   Capotondi, G. Biasiol and L. Sorba