Author: "Masato Shimono" - Searchworks@Jio Institute Digital Library Search Results

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Author: Masato Shimono
Subjects: Condensed Matter::Quantum Gases, Physics, Spinor, Physics and Astronomy (miscellaneous), Discretization, High Energy Physics::Lattice, Global anomaly, Fermion, Classical mechanics, Gravitational field, Lattice (order), Effective action, Mathematical physics, Gravitational anomaly
Abstract: Kahler's geometrical description of fermions without the use of spinors is extended to the systems on general discretized manifolds. It is shown that this prescription gives a generalized version of the Susskind fermions. In this framework the interaction between fermions and lattice gravity is studied. The effective action obtained from the functional integrals in two·dimensional space· time shows the existence of the lattice analogues of the trace anomaly and the gravitational anomaly.
Published: 1990

Author: Kazuaki Kobayashi, Hirokazu Takaki, Masato Shimono, Nobuhiko Kobayashi, and Kenji Hirose
Abstract: Nanostructured TiN(001) dot/MgO(001)-4 × 4 and 5 × 5 superlattices based on a repeated slab model have been investigated. The electronic states of TiN(001) dot/MgO(001)-4 × 4 and 5 × 5 superlattices were obtained by using the total-energy pseudopotential method. The internal atomic coordinates in a unit cell were fully relaxed. We consider two types of TiN dot structures as rectangular and rectangular parallelepiped. They all correspond to semiconductor, although relaxed rectangular parallelepiped TiN(001) dot/MgO(001)-2 × 2 and 3 × 3 superlattices correspond to metallicity. A bandgap value of the rectangular TiN(001) dot/MgO(001) superlattice increases with increasing the size of the MgO substrate, although the difference in the band gap between 4 × 4 and 5 × 5 is small at approximately 0.01 eV. Their electronic properties depend on the shape of the TiN dot and the size of the MgO substrate. The bandgap value is corrected by using a generalized density-functional theory. [ABSTRACT FROM AUTHOR]
Published: 2019
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Author: Kazuaki Kobayashi, Hirokazu Takaki, Masato Shimono, Nobuhiko Kobayashi, and Kenji Hirose
Abstract: Various nanostructured TiN(001)/MgO(001) superlattices based on a repeated slab model with a vacuum region have been investigated by the total energy pseudopotential method. They are rectangular and rectangular parallelepiped TiN(001) dot structures on MgO(001)-2×2 and 3×3 substrates. A rectangular TiN(001) structure on a MgO(001)-2×1 substrate has also been calculated. Their detailed electronic and internal lattice properties were investigated systematically. The internal atomic coordinates in a unit cell were fully relaxed. The rectangular TiN(001) structure on the MgO(001)-2×1 superlattice, which is not a dot owing to its periodicity, corresponds to metallicity. The electronic states of relaxed rectangular TiN(001) dot/MgO(001)-2×2 and MgO(001)-3×3 superlattices are semiconducting. All relaxed rectangular parallelepiped TiN(001) dot/MgO(001)-2×2 and MgO(001)-3×3 superlattices correspond to metallicity. The electronic properties depend on the shape of the TiN dot and the size of the MgO substrate. [ABSTRACT FROM AUTHOR]
Published: 2017
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