ON THE THEORY OF SPIN-DEPENDENT TUNNELING IN THE SCANNING TUNNELING MICROSCOPE - ANTIFERROMAGNETIC CRYSTAL FERROMAGNETIC TIP

We present calculations of spin-dependent tunneling in the scanning tunneling microscope in the case of the spin-polarized tip and sample. Analysis shows that the tunneling current contains two parts. The spin-dependent part of the tunneling current is proportional to the scalar product of the local magnetization at the tip apex and crystal surface. The spin-dependent part of the tunneling current has the usual structure. It is shown that in the case of a large tip-sample separation, the combined measurements of the tunneling current at the different points on the surface, in principle, allow to restore the spin-polarized density of states. In the general case of a small tip-small separation it is completely impossible to separate the spin-dependent and spin-independent parts of the density of states at the surface.