title: Universal medium-range order of amorphous metal oxides.
abstract: We propose that the structure of amorphous metal oxides can be regarded as a dual-dense-random-packing structure, which is a superposition of the dense random packing of metal atoms and that of oxygen atoms. Our ab initio molecular dynamics simulations show that the medium-range order of amorphous HfO2, ZrO2, TiO2, In2O3, Ga2O3, Al2O3, and Cu2O is characterized by the pentagonal-bipyramid arrangement of metal atoms and that of oxygen atoms, and prove the validity of our dual-random-sphere-packing model. In other words, we find that the pentagonal medium-range order is universal independent of type of metal oxide.
authors.affiliation: Nanosystem Research Institute (NRI), "RICS," National Institute of Advanced Industrial Science and Technology (AIST), Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Nishio
authors.forename: Takehide
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Hisao
authors.initials: H
authors.lastname: Nakamura