A high positive magnetoresistance (MR), 78%, is observed at 2 K on the ab plane of the diamagnetic RuSb2+ semiconductor. On the ac plane, MR is 44% at 2 K, and about 7% at 300 K. MR at different temperatures do not follow the Kohler's rule. It suggests that the multiband effect plays a role on the carrier transportation. RuSb2+ is a semiconductor with both positive and negative carriers. The quantum interference effect with the weak localization correction lies behind the high positive MR at low temperature. Judged from the ultraviolet-visible spectra, it has a direct band gap of 1.29 eV. The valence band is 0.39 eV below the Fermi energy. The schematic energy band structure is proposed based on experimental results.
Keywords: RuSb2; magnetoresistivity; weak localization.