Papers by Keyword: Pseudogap

Abstract: This research studied the isotope effect coefficient of high temperature superconductors. The model used one-band superconductor which considered the competition of superconducting gap and pseudogap in the below crossover temperature region. The isotope effect coefficient is derived and approximation in simplify form. We find that the isotope effect coefficient is decreased as the critical temperature Tc and the crossover temperature T* ratio Tc/T* increased.

Abstract: The characteristics of chemisorptions, such as the pseudogap, forbidden bandwidth, energy curve, the trend of Fermi level in the graphics and the density of states at the Fermi level and so on, were given for the chemisorptions of atom on the Si (001) surface from the density of states. From these densities of states’ curves, the characteristics of chemisorptions were analyzed and compared to for different elements absorption on the Si (001) surface. The density of states for chemisorptions is different for the different elements.

Abstract: The density of states was given for the chemisorptions of atom on the Si (111) surface. From these curves, the characteristics, such as the pseudogap, forbidden bandwidth, energy curve, the trend of Fermi level in the graphics and the density of states at the Fermi level and so on, were analyzed and compared to for different elements absorption on the Si (111) surface. The density of states for chemisorptions is different for the different elements.

Abstract: The band structures were given by study on the chemisorptions of atom on the Si (100) surface. From these curves, the pseudogap, forbidden bandwidth, the trend of Fermi level in the graphics at the Fermi level were analyzed and compared for different elements absorption. The conclusion is that the electrical conductivity of Cu, Na is the best, followed by C, the last is the Si.

Abstract: The exact formula of T_c’s equation of two-band s-wave superconductors with Pseudogap in weak-coupling limit are derived by considering the influence of interband interaction. The pairing interaction in each band consisted of 2 parts the electron-phonon interaction and non-electron-phonon interaction are included in our model. It was found that the critical temperature is increased as Pseudogap, phonon coupling of 1^st band constant and interband phonon coupling constant increased.

Abstract: While the Heusler-type Fe₂VAl compound exhibits a semiconductor-like behavior in electrical resistivity, doping of quaternary elements causes a sharp decrease in the low-temperature resistivity ρ and a large enhancement in the Seebeck coefficient S. Substantial enhancement in S can be explained on the basis of the electronic structure where the Fermi level shifts slightly from the center of a pseudogap either up- or downward depending on doping. In particular, a slight substitution of Si for Al leads to a large power factor (P = S²/ρ) of 5.5×10^-3 W/m K² at around room temperature.