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We studied electrical transport in dilute magnetic semiconductors, which is determined by scattering free carriers by localized magnetic moments. While calculating the scattering time and the mobility of the majority and minority-spin carriers, we took into account both the effects of thermal spin fluctuations and of the spatial disorder of magnetic atoms. These effects are responsible for the magnetic-field dependence of electrical resistivity. Namely, the application of the external magnetic field suppresses the thermodynamic spin fluctuations, thus promoting negative magnetoresistance (MR). Simultaneously, scattering by built-in spatial fluctuations of the atomic spins increases with the magnetic field. The latter effect is due to the growth of the magnitude of random local Zeeman splittings with the magnetic field. It promotes positive MR. We discuss the role of the above effects on MR of semiconductors where magnetic impurities are isoelectronic. Index Terms--Magnetoresistance, semiconductor, spin scattering.

The perpendicular to the chains in the [In.sub.4][Se.sub.3](001) surface is analyzed by a weaker but discernable dispersion perpendicular to both the chain direction and the cleavage plane. A band is identified near the valence band maximum that has fallen into a gap of the projected bulk band structure at the surface Brillouin zone (BZ) edge that might well be a surface state.

Abstract: The layered In4Se3 system does have a bulk band structure (i.e. discernable and significant band dispersion) perpendicular to the cleavage plane. Band widths (the extent of dispersion) of 300meV or more are observed, for In-p and Se-p weighted bands within the valence region, and is indicative of a bulk band structure. Two-dimensionality of state is clearly not conserved, and there must exist interactions between layers sufficient to support a bulk band structure. [Copyright &y& Elsevier]