Reconciling results of tunnelling experiments on (Ga,Mn)As

A theoretical model is presented which allows to reconcile findings of scanning tunnelling spectroscopy for (Ga,Mn)As [Richardella et al. Science 327, 66 (2010)] with results for tunneling across (Ga,Mn)As thin layers [Ohya et al. Nature Phys. 7, 342 (2011); Phys. Rev. Lett. 104, 167204 (2010)]. According to the proposed model, supported by a self-consistent solution of the Poisson and Schroedinger equations, a nonmonotonic behaviour of differential tunnel conductance as a function of bias is associated with the appearance of two-dimensional hole subbands rather in the GaAs:Be electrode than in the (Ga,Mn)As layer.