MAGNETIC IMPURITY INTERACTIONS IN A QUANTUM-WELL ON THE BASE OF IV-VISEMICONDUCTORS

We study the indirect exchange interaction of magnetic impurities via 2D excitations in a quantum well on the base of IV-VI narrow-gap semic onductors. The energy spectrum of 2D excitations takes into account th e nonparabolicity of dispersion as well as the strong spin-orbit inter action. The calculations are performed for the case when the main mech anism is an exchange by virtual electron-hole pairs. It means that we assume the Fermi level to lie inside the energy gap, and the temperatu re to be small, T much-less-than epsilon0. It is shown that at large d istances, R much-greater-than v/epsilon0 (2epsilon0 is the excitation energy for nearest size-quantized subbands, nu the interband interacti on parameter), the antiferromagnetic interaction of pairs dominates, s o that the impurity spins tend to be directed along the heterojunction plane perpendicular to the vector connecting the impurities. The inte raction contains both the Heisenberg and pseudodipole terms.