Fermionic lattice models and electronic correlations: Magnetism and superconductivity

Estudiamos un sistema formado por M dímeros a través del modelo de Hubbard de dos sitios semillenos, es decir, con dos electrones. Para nuestro enfoque usamos la tercera versión de la mecánica estadítica no extensiva como herramienta para calcular los parámetros termodinámicos y magnéticos tales como la entropía, la energía interna, la magnetización y el calor específico. En las simulaciones, variamos los valores del índice entropico q entre 1 y 2, de modo que q = 1.0, 1.4, 1.7 y 2.0. Estos valores son interesantes para el estudio de sistemas magnéticos pequeños. Encontramos regiones de temperatura crítica usando el modelo simple de Hubbard, es decir, sin interacción entre los sitios. por otro lado, añadiendo el término de interacción, encontramos un alargamiento y un corrimiento de los parámetros termodinámicos comparado a los otenidos mediante el modelo simple. Más aún, encontramos algunos casos en que las regiones de temperatura crítica desaparecen.

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“…Taking into account the extended Hubbard model [8], we add another energy term, the intersite Coulombian interaction…”

Section: Half-filled Two-site Hubbard Modelmentioning

confidence: 99%

“…We study the extended Hubbard model and found another way of calculating the probabilities, as we explain it below. We discuss the half-filled two-site Hubbard model [8] and the third version of the Nonextensive Statistical Mechanics. Next, we calculate the energy eigenvalues for the Hamiltonian matrix, and also explain how to find the energy eigenvectors.…”

mentioning

confidence: 99%

Simulaciones computacionales para el modelo de Hubbard extendido usando la mecánica estadística no extensiva

Navarro

Flores

2011

Rev. Inv. Fis.

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Grand canonical ensemble of the extended two-site Hubbard model via a nonextensive distribution

2013

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In this study, ZnO was doped with 0.01% Mn and it is grown on p-Si by the sol-gel spin-coating method. Obtained the thin film was studied that to understand the effect of 0.01% Mn-doping ratio on the optical and electrical properties of ZnO structure. In this context, first, the morphological structure of the thin film was studied with the use of atomic force microscopy (AFM). The surface structure was obtained homogeneous, and roughness and fiber size were calculated between 27.2-33.6 and 0.595-0.673 nm, respectively. Second, the optical properties were characterized via ultravioletvisible (UV-Vis) spectrophotometry. Third, the effect of light intensity on junction properties of the photodiode was studied. The current-voltage (I-V) of the photodiode was measured under dark and at the different intensities of illumination. Obtained results showed that the current of photodiode was increased with the intensity of illumination from 6.41 9 10 -7 to 5.32 9 10 -4 A. These results indicate that photocurrent under illumination is higher than the dark current. After that, the other parameters of the photodiode such as barrier height and ideality factor were determined from forwarding I-V plots using the thermionic emission model that the barrier height and the ideality factor were found 0.74 eV and 5.3, respectively. On the other hand, the capacitance-voltage (C-V) was measured at the different frequencies. The C-V characteristic shown that C-V characteristic of the photodiode was changed depends on increasing frequency. In addition, the interface density (D it ) value was decreased by increasing frequency too. Similarly, the serial resistance of the photodiode was also decreased by increasing frequency. Received all these results indicated that Mn-doped ZnO thin film sensitive to light and due to this property, it can be used for different optoelectronic applications as a photodiode and photosensor.

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Fermionic lattice models and electronic correlations: Magnetism and superconductivity

Cited by 2 publications

References 28 publications

Simulaciones computacionales para el modelo de Hubbard extendido usando la mecánica estadística no extensiva

Simulaciones computacionales para el modelo de Hubbard extendido usando la mecánica estadística no extensiva

Grand canonical ensemble of the extended two-site Hubbard model via a nonextensive distribution

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