Momoji Kubo

Molecular-dynamics simulations were performed to clarify the structures of SrO and BaO layers on a ${\mathrm{SrTiO}}_{3}(001)$ substrate at the atomic level, and to predict an appropriate buffer layer for ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}/{\mathrm{SrTiO}}_{3}$ heterojunction. The atomic structure of these layers grown on a ${\mathrm{SrTiO}}_{3}(001)$ substrate terminated on the ${\mathrm{TiO}}_{2}$ atomic plane was investigated. From the analysis of the angle di

Ultraflat and damage-free single-crystal diamond is a promising material for use in electronic devices such as field-effect transistors. Diamond surfaces are conventionally prepared by the chemical mechanical polishing (CMP) method, although the CMP efficiency remains a critical issue owing to the extremely high hardness of diamond. Recently, OH radicals have been demonstrated to be potentially useful for improving the CMP efficiency for diamond; however, the underlying mechanisms are still elus

We clarified here an epitaxial growth mechanism of ZnO(0001) surface on an atomic scale, by using molecular-dynamics crystal-growth simulations. It was observed that the crystal growth starts at the step of ZnO(0001), but not at the terrace of ZnO(0001). This phenomenon is clearly justified from the coordination number of adsorbed ZnO molecules on the ZnO(0001) surface. The ZnO molecule can form bonds with the smooth ZnO surface through only single coordination since the topmost surface is const

Slide-ring (SR) gels with slidable cross-linked cyclic molecules exhibit considerably higher fracture toughness than conventional fixed cross-link (FC) gels. However, the mechanical properties of SR gels are still unsatisfactory, and thus, these gels cannot be practically applied. Therefore, molecular scale insights into the fracture mechanism of SR gels are required to improve their mechanical properties. This study conducted tensile strain simulations of FC and SR gels using a coarse-grained m

The super-low friction mechanism of fluorine-terminated diamond-like carbon (F-terminated DLC) is investigated by using our tight-binding quantum molecular dynamics code and compared with that of hydrogen-terminated DLC (H-terminated DLC). Under a contact pressure of 1 GPa, F- and H-terminated DLC show smooth sliding and low friction coefficients of 0.07 and 0.04, respectively. The ion radius of fluorine is larger than that of hydrogen, which leads to the larger asperity of the F-terminated DLC