D ferromagnetism in black phosphorous oxide caused by surface P-O bonds

Abstract

The room-temperature d0 ferromagnetism in black phosphorous (BP) oxide is investigated experimentally and theoretically. Electrochemical oxidation does not alter the single-crystal structure of BP and the degree of oxidation depends on the oxidation time, thereby resulting in changeable d0 ferromagnetism caused by surface P-O bonds. First-principles calculation reveals that different surface P-O bonds have different binding energies and contributions to the ferromagnetism and the bridge and dangling oxygen atoms are responsible for the observed ferromagnetism which stems from p orbital spin polarization of the oxygen and phosphorus atoms.