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First-principles study on the electronic structure and optical properties of T12Cd2(SO4)3 and Rb2Cd2(SO4)3 下载免费PDF全文
With the help of ab initio full-potential linearized augmented plane wave (FPLAPW) method, calculating the electronic structure and linear optical properties is carried out for XCd2(SO4)3 (X =Tl, Rb). The results show that Tl2Cd2(SO4)3 (TlCdS) has a larger band gap than Rb2Cd2(SO4)3 (RbCdS) and the energy bands for RbCdS are more dispersive than those of TlCdS. From their partial densities of states (PDOS), we have observed that the hybridization between S ionic 2p and O atomic 2p orbitals forms SO4 ionic groups. The remarkable difference between RbCdS and TlCdS is, however, the degree of hybridization between cation (Tl and Rb) and its surrounding oxygen atoms. In the view of quantum chemistry, the strong p-d hybridization indicates the existence of their cation ionic bonds (Cd-O, Rb-O, and Tl-O). The calculations of TlCdS and RbCdS show their optical properties to be less anisotropic. Their anisotropies in the optical properties mainly occur in a low photon energy region of 5-16 eV. 相似文献
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Full potential linearized augmented plane wave (FPLAPW) method calculations are carried out for semiconducting orthorhombic BaSi2. The optical properties and the origin of the different optical transitions are investigated. Our calculated band gap of 1.0918eV is indirect, which is in good agreement with the experimental result. The bonds between Ba and Si are considered to be electrovalent bond. The anlsotropy in the imaginary part ε2(w) and real part εl(w) of the optical dielectric tensor are analysed. The contributions of various transition peaks are explained from the imagnary part of the dielectric function. 相似文献
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用阳阴离子交换柱和流动注射分析组合,建立了在线预处理和预分离同时测定磷和硅的FIA方法。用本法测定了头发、淡菜、茶叶、马尾藻和大米中的硅和磷。方法的测定范围为1.0mg/L-24mg/L(PL4^3-),0.5mg/L-12mg/L(SiO3^2-),回收率:96.7%-99.0%(PO4^3-),100%-102%(SiO3^2-);RSD(PO4^3-)=1.3%,RSD(SiO3^2-)=1.8%。 相似文献
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Continuous Variable Entanglement and Violation of Bell Inequality for Two Modes in a Three-Level Cascade Atomic System 下载免费PDF全文
Continuous variable entanglement and violation of Bell inequality for two modes are investigated in a three-level cascade atomic system. Entanglement of the system is demonstrated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000)2722]. Violation of Bell inequality is studied within the framework of a quantum theory of multiwave mixing. It is shown that there are some states that are entangled but do not violate the Bell inequality. 相似文献
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Charge transport and shot noise on the surface of a topological insulator with a magnetic modulation 下载免费PDF全文
In this paper, we investigate the transport features and the Fano factor of Dirac electrons on the surface of a three-dimensional topological insulator with a magnetic modulation. We consider a hard wall bounding condition on the edge of the topological insulator, which implies that a surface state of the topological insulator is insulating. We find that a valley of conductivity at the Dirac point is associated with a Fano factor peak, and more interestingly, this topological metal changes from insulating to metallic by controlling the effective exchange field. 相似文献
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Temperature dependence of the energy-level shift induced by the Bose—Einstein condensation of photons 下载免费PDF全文
We investigate the energy-level shift of a hydrogen atom in a two-dimensional optical microcavity, where there exists a Bose-Einstein condensation of photons. It is found that below the critical temperature T c , the energy-level shift of the bound electron is dependent on temperature, and it is a monotonically increasing function of the absolute temperature T . Especially, at the absolute zero temperature, the energy-level shift entirely comes from the Lamb shift, and the atom can be treated approximately, that is, in vacuum. 相似文献