| 1. |
- Fu, Qiang, et al.
(författare)
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Exploring at nanoscale from first principles
- 2009
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Ingår i: FRONTIERS OF PHYSICS IN CHINA. - : Springer Science and Business Media LLC. - 1673-3487 .- 1673-3606. ; 4:3, s. 256-268
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Tidskriftsartikel (refereegranskat)abstract
- Systems at the nanoscale can exhibit distinctive and unexpected properties in electrical, magnetic, mechanical, and chemical aspects. Understanding these properties not only is of importance from the fundamental scientific view but also offers great opportunities for future applications. Theoretical calculations can provide important information to interpret, modify, and predict the novel properties of objects at the nanoscale and therefore play a significant role in the process of exploring the nano world. In this review, six different areas are briefly presented, namely, prediction of new stable structures, modi. cation of properties (especially the electronic structures), design of novel devices for applications, the structures and catalytic effects of clusters, the mechanical and transport properties of gold nanowires, and improvement of materials for hydrogen storage. Based on these examples, we show what can be done and what can be found in the investigations of nanoscale systems with participation of theoretical calculations.
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| 2. |
- Gao, Bin, et al.
(författare)
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Simulation of electronic structure of nanomaterials by central insertion scheme
- 2009
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Ingår i: FRONTIERS OF PHYSICS IN CHINA. - : Springer Science and Business Media LLC. - 1673-3487 .- 1673-3606. ; 4:3, s. 307-314
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Tidskriftsartikel (refereegranskat)abstract
- An effective central insertion scheme (CIS) that allows to study the electronic structure of nanomaterials at the first principles level is introduced. Taking advantage of advanced numerical methods, such as the implicitly restarted Arnoldi method (IRAM) and spectral transformation, together with efficient parallelization technique, this scheme can provide accurate electronic structures and properties of one-, two-, and three-dimensional nanomaterials with only a fraction of computational time required for conventional quantum chemical calculations. Electronic structures of several nanostructures, such as single-walled carbon nanotubes of sub-100 nm in length, silicon nanoclusters of sub-6.5 nm in diameter and metal doped silicon clusters, calculated at hybrid density functional level are presented.
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| 3. |
- Hao, Jiaming, et al.
(författare)
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Manipulate light polarizations with metamaterials : From microwave to visible
- 2010
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Ingår i: Frontiers of Physics in China. - : Springer Science and Business Media LLC. - 1673-3487 .- 1673-3606. ; 5:3, s. 291-307
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Tidskriftsartikel (refereegranskat)abstract
- Polarization is an important characteristic of electromagnetic (EM) waves, and efficient manipulations over EM wave polarizations are always desirable in practical applications. Here, we review the recent efforts in controlling light polarizations with metamaterials, at frequencies ranged from microwave to visible. We first presented a 4 x 4 version transfer matrix method (TMM) to study the scatterings by an anisotropic metamaterial of EM waves with arbitrary propagating directions and polarizations. With the 4 x 4 TMM, we discovered several amazing polarization manipulation phenomena based on the reflection geometry and proposed corresponding model metamaterial systems to realize such effects. Metamaterial samples were fabricated with the help of finite-difference-time-domain (FDTD) simulations, and experiments were performed to successfully realize these ideas at both microwave and visible frequencies. Efforts in employing metamaterials to manipulate light polarizations based on the transmission geometry are also reviewed.
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| 4. |
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| 5. |
- Tjörnhammar, Richard, 1982-
(författare)
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A first-principles study on the electronic structure ofone-dimensional [TM(Bz)]∞ polymer(TM= Y, Zr, Nb, Mo, and Tc)
- 2009
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Ingår i: Frontiers of Physics in China. - : Springer. - 1673-3487 .- 1673-3606. ; 4:3, s. 403-407
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Tidskriftsartikel (refereegranskat)abstract
- A systematic density functional theory (DFT) study has been performed to investigate the electronicand magnetic properties of one-dimensional sandwich polymers constructed with benzene (Bz) and thesecond-row transition metal (TM = Y, Zr, Nb, Mo, and Tc). Within the framework of generalized gra-dient approximation (GGA), [Tc(Bz)]∞ is a ferromagnetic half-metal, and [Nb(Bz)]∞ is a ferromagneticmetal. With the on-site Coulomb interaction for 4d TM atoms being taken into account, [Tc(Bz)]∞keeps a robust half-metallic behavior, while [Nb(Bz)]∞ becomes a spin-selective semiconductor. Thestability of the half-metallic [Tc(Bz)]∞ polymer is discussed based on magnetic anisotropy energy(MAE). Compared with 0.1 meV per metal atom in [Mn(Bz)]∞ , the calculated MAE for [Tc(Bz)]∞ is2.3 meV per metal atom. Such a significantly larger MAE suggests that Tc(Bz)]∞ is practically morepromising than its first-row TM equivalent.
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| 6. |
- Wang, Jing, et al.
(författare)
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Photonic crystal surface mode microcavities
- 2010
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Ingår i: FRONTIERS OF PHYSICS IN CHINA. - : Springer Science and Business Media LLC. - 1673-3487 .- 1673-3606. ; 5:3, s. 260-265
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Tidskriftsartikel (refereegranskat)abstract
- Our recent research on surface mode optical microcavities based on two-dimensional photonic crystals (PhCs) was reviewed in this paper. We presented the design, fabrication and characterization of high quality (Q) factor surface mode microcavities. Realizations of these PhCs were based on both amorphous silicon-on-insulator (SOI) structures and crystalline SOI structures.
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