Theoretical and experimental investigation of the excellent p–n control in yttrium aluminoborides

First-principles calculations were carried out to elucidate the excellent control of p–n characteristics recently reported for yttrium aluminoborides YxAlyB14 with different occupancies of Al sites . Such control of the occupancy of metal sites in borides is unusual. Calculations based on detailed x-ray diffraction data reveal a stable configuration of the atomic sites, indicating that such variation in occupancy is possible. A shift from positive through zero to negative values of the Seebeck coefficient is also clearly illustrated by determining the density of states for different configurations.