We propose an efficient method to compute the dielectric permittivity of nanostructures by combining first principles density functional perturbation theory with effective medium theory. Specifically, ultrathin axially symmetric ferroelectric PbTiO3 nanowires are considered. As established previously by Pilania and Ramprasad (Phys Rev B 82:155442, 2010), (4 9 4) PbO-terminated nanowire and (4 9...

We used first-principles methods to generate amorphous TiO2 (a-TiO2) models and our simulations lead to chemically ordered amorphous networks. We analyzed the structural, electronic, and optical properties of the resulting structures and compared with crystalline phases. We propose that two peaks found in the Ti–Ti pair correlation correspond to edge-sharing and corner-sharing Ti–Ti pairs. Resu...

Three design principles are advanced for multi-user educational videogames. First, they should support situative embodiment in academic knowledge, where personally meaningful activities and coherent narratives foster collective engagement. Second, they should offer multiple levels and forms of meaningful assessment and the opportunity to succeed, fail, and try again. Third, they should provide ...