Vacancy induced magnetism in WO3

• Published in: The European physical journal. B, Condensed matter physics Vol. 86; no. 6; p. 273
• Main Authors: Baldissera, Gustavo, Persson, Clas
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2013; EDP Sciences
• Subjects: Augmented-Wave Method; Complex Systems; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fluid- and Aerodynamics; Magnetic properties and materials; Physics; Physics and Astronomy; Regular Article; Solid State Physics; Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.); Solid State and Materials; Tungsten oxide; Band structure; Local magnetic moment; Vacancies; PAW calculation; Magnetic moments; Local spin density approximation; Ferromagnetism; Electronic density of states; Defect formation
• ISSN: 1434-6028; 1434-6036; 1434-6036
• DOI: 10.1140/epjb/e2013-40014-7

The possibility to obtain ferromagnetic (FM) phase from native defects in WO 3 is investigated by theoretically analyzing six different crystalline structures. The local magnetic moment from vacancies is calculated using the projector augmented wave method in combination with the local spin density approximation including a Coulomb correction (LSDA + U) of the W d -states. We find that tungsten vacancies V W can induce a magnetic phase of ~3.5 μ B / V W with a local magnetic moment on the oxygen atoms of at most ~1 μ B / V W , whereas corresponding oxygen vacancies V O have no impact on the magnetic coupling. Intriguingly, although the six crystalline structures have very comparable bonds, the magnetic moment generated by the cation vacancies is different, showing higher local magnetic moments for WO 3 structures with low crystalline symmetry. The results indicate that WO 3 : V W cannot induce a hole-mediated FM phase, and instead V W in WO 3 induces a local magnetic moment on the unpaired states at surrounding O atoms.