INTERACTION EFFECTS AT THE MAGNETIC-FIELD-INDUCED METAL-INSULATOR-TRANSITION IN SI SIGE SUPERLATTICES/

A metal-insulator transition was induced by in-plane magnetic fields u p to 27 T in homogeneously Sb-doped Si/SiGe superlattice structures. T he localisation is not observed for perpendicular magnetic fields. A c omparison with magnetoconductivity investigations in the weakly locali sed regime shows that the delocalising effect originates from the inte raction-induced spin-triplet term in the particle-hole diffusion chann el. It is expected that this term, possibly together with the singlet particle-particle contribution, is of general importance in disordered n-type Si bulk and heterostructures. (C) 1998 Elsevier Science Ltd. A ll rights reserved.