114 resultados para Local density of states - (LDOS)

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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We theoretically investigate the local density of states (LDOS) probed by an STM tip of ferromagnetic metals hosting a single adatom and a subsurface impurity. We model the system via the two-impurity Anderson Hamiltonian. By using the equation of motion with the relevant Green's functions, we derive analytical expressions for the LDOS of two host types: a surface and a quantum wire. The LDOS reveals Friedel-like oscillations and Fano interference as a function of the STM tip position. These oscillations strongly depend on the host dimension. Interestingly, we find that the spin-dependent Fermi wave numbers of the hosts give rise to spin-polarized quantum beats in the LDOS. Although the LDOS for the metallic surface shows a damped beating pattern, it exhibits the opposite behavior in the quantum wire. Due to this absence of damping, the wire operates as a spatially resolved spin filter with a high efficiency. © 2013 American Physical Society.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this work, we investigate theoretically the spin-resolved local density of states (SR-LDOS) of a ferromagnetic (FM) island hybridized with an adatom, which is described by the Single Impurity Anderson Model (SIAM). Our results are comparable with Scanning Tunneling Microscope (STM) experimental data. © 2012 Springer Science+Business Media, LLC.

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Low frequency admittance measurements are used to determine the density of interface states in metal-insulator-semiconductor diodes based on the unintentionally doped, p-type semiconductor poly(3-hexylthiophene). After vacuum annealing at 90 degrees C, interface hole trapping states are shown to be distributed in energy with their density decreasing approximately linearly from similar to 20x10(10) to 5x10(10) cm(-2) eV(-1) over an energy range extending from 0.05 to 0.25 eV above the bulk Fermi level. (c) 2008 American Institute of Physics.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Space-charge-limited currents measurements have been carried out on undoped amorphous poly p-phenylene sulfide. The scaling law is checked for different samples with varying thickness, and J-V data analyzed. The position of the quasi-Fermi level and the density of states was obtained.

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In a finite size bag like picture consisting of quarks (2 flavour) and gluons with SU(3) colour singlet restriction on the partition function and the chemical potential μ ≠ 0 with the constraint that the baryon number b = 0 and b = 1 for mesons and baryons, respectively we find a very good agreement with baryon density of states upto 2 GeV and with mesonic ones upto 1.3 GeV. Similar to a hadron-scale string theory our calculation also suggests that beyond 1.3 GeV there should exist exotic mesons.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciência dos Materiais - FEIS

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciência dos Materiais - FEIS

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)