High Positive MR and Energy Band Structure of RuSb.

A high positive magnetoresistance (MR), 78%, is observed at 2 K on the plane of the diamagnetic RuSb semiconductor. On the 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. RuSb 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.