Enhanced ferromagnetism induced by structural phase transitions in Co2As1−xPx

P doping in Co2As induces two structural transitions, resulting in an enhanced ferromagnetic state at intermediate P compositions. In Co2As1−xPx, doping induces a room temperature α-to-β structural distortion around x=0.04, similar to what temperature (T=725 K) does in the parent compound (x=0). The resulting β phase displays an enhanced ferromagnetic ground state. Close to x=0.85, a hexagonal-to-orthorhombic phase transition occurs, concomitant with the quenching of the magnetic order. Band structure calculations for the three different phases confirm the experimental observations while revealing remarkably high charge carrier polarization rate for the β phase.