We present the in-plane and c-axis penetration depths of the underdoped cuprates. The pseudogap phase is addressed within the framework of the ordered d-density wave (DDW). The above scenario is considered using a mean-field calculation of the tight binding model which incorporates two types of...

A method for estimating, via the Monte-Carlo simulation, the most often realized diffusion mechanisms in 2D ordered structures is presented. Taking as an example the diffusion of oxygen ions in 123 — YBCO high temperature superconductor we propose several diffusion mechanisms and show to what...

The insulator-metal (IM)-transition in Pr<Subscript>1-x</Subscript>Ca<Subscript>x</Subscript>MnO<Subscript>3</Sub script> (PCMO) is of particular interest because it can be induced by a variety of external forces, such as magnetic and electric fields, photon exposure and hydrostatic pressure. In this paper, we present a comparative study of the IM-transition in...<//sub></subscript></subscript></subscript>

Transport properties of the charge ordering compound β-Na<Subscript>0.33</Subscript>V<Subscript>2</Subscript>O<Subscript>5</Sub script> are studied in the temperature range from 30 K to 300 K using current driven DC conductivity experiments. It is found that below the metal-insulator transition temperature (<InlineEquation ID="Equ2"> <EquationSource Format="TEX">$T_{MI}= 136~K$</EquationSource> </InlineEquation>) this material shows a nonlinear...</equationsource></inlineequation><//sub></subscript></subscript></subscript>

We present a comprehensive optical study of the narrow gap FeSb<Subscript>2</Subscript> semiconductor. From the optical reflectivity, measured from the far infrared up to the ultraviolet spectral range, we extract the complete absorption spectrum, represented by the real part σ<Subscript>1</Subscript>(ω) of the complex optical...</subscript></subscript>