Abstract
Band-structure calculations within the local spin-density approximation are presented in order to investigate the electronic and magnetic properties of the zigzag spin-chain compound In2VO5. The essential structural feature of the system is a double chain of VO6 octahedra, which leads to competing intrachain and interchain magnetic couplings. Frustration of the spin chains is expected for the proposed antiferromagnetic ordering at low temperatures. However, the band-structure calculations indicate that the experimental room-temperature crystal structure are incompatible with antiferromagnetism. Both the intrachain and interchain couplings are found to be ferromagnetic.