Vacancy induced magnetism in WO3

• Published in: The European physical journal. B, Condensed matter physics Condensed matter physics, 2013, Vol.86 (6), p.273, Article 273
• Main Authors: Baldissera, Gustavo, Persson, Clas
• Format: Article
• Language: English
• 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.)
• 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.