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Register a new userInfluence of the Surface Structure and Vibration Mode on the Resistivity of Cu Films
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The influence of the surface structure and vibration mode on the resistivity of Cu films and the corresponding size effect are investigated. The temperature dependent conductivities of the films with different surface morphologies are calculated by the algorithm based upon the tight-binding linear muffin-tin orbital method and the Greens function technique. The thermal effect is introduced by setting the atomic displacements according to the Gaussian distribution with the mean-square amplitude estimated by the Debye model. The result shows that the surface atomic vibration contributes significantly to the resistivity of the systems. Comparing the conductivities for three different vibration modes, it is suggested that freezing the surface vibration is necessary for practical applications to reduce the resistivity induced by the surface electron-phonon scattering.
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Charged domain walls form spontaneously in Cu-Cl boracite on cooling through the phase transition. These walls exhibit changed conductivity compared to the bulk and motion consistent with the existence of negative capacitance. Here, we present the dielectric permittivity and DC resistivity of bulk Cu-Cl boracite as a function of temperature (-140 {deg}C to 150 {deg}C) and frequency (1 mHz to 10 MHz). The thermal behaviour of the two observed dielectric relaxations and the DC resistivity is discussed. We propose that the relaxations can be explained by the existence of point defects, most likely local complexes created by a change of valence of Cu and accompanying oxygen vacancies. In addition, the sudden change in resistivity seen at the phase transition suggests that conductive domain walls contribute significantly to the conductivity in the ferroelectric phase.
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