arXiv subjects

M. Sztyren

Publications and source records attributed to M. Sztyren.

6 recordsLinked to original sources

arXiv2009

Higher-grade hybrid model: enhancement of supercoductivity

The discussion of enhancement of superconductivity is presented in the framework of the higher-grade hybrid model of layered superconductors. The enhancement is considered from the following two points of view: (i) as a result of long-range couplings with respects to the short distance ones, and (ii) the enhancement of 3D superconductivity with respect to the 2D. Two important cases are distinguished: homogeneous bulk supercoducting materials and superconducting structures composed of a finite number of layers.

cond-mat.supr-con↗

arXiv2008

Ground states for three-layer hybrid superconductor

A superconducting hybrid structure composed of three layers is considerated.The 2D layers interact mutually by higher grade inter-layer couplings.We determine the possible superconducting modes. Those solutions enable to discuss the conditions for the onset and enhancement of 3D superconductivity in such a structure.

cond-mat.supr-con↗

arXiv2007

Fundamental excitations in layered superconductors with long-range Josephson couplings

The present paper develops the ideas introduced in {\em cond-mat/0312673}. The construction of a hybrid discrete-continuous model of layered superconductors is briefly presented. The model bases on the classic Lawrence-Doniach scenario with admitting, however, long-range interactions between atomic planes. Moreover, apart from Josephson couplings they involve the proximity effects. The range of interactions, K, can, in principle, be arbitrary large. The solutions corresponding to the range K=2 are exposed. The fundamental excitations are understood as deviations from stable ground states.The formulae for energy of those excitations are constructed. The possible shapes of dispersion curves are analysed. For each type of shape the corresponding values of physically measurable quantities like effective maa and bandwidth are expressed by coupling parameters.

cond-mat.supr-con↗

arXiv2006

Layered superconductors with long-range Josephson couplings

The present paper is an extension of 'cond-mat/0312673'. The construction of a hybrid discrete-continuous model of layered superconductors is presented. The model bases on the classic Lawrence-Doniach scenario with admitting, however, long-range interactions between atomic planes. Moreover, apart from Josephson couplings they involve the proximity effects. The range of interactions can, in principle, be arbitrary large. The solutions corresponding to the range K=2 are found. The mechanism of enhancement of superconductivity caused by the proximity effect and the presence of higher Josephson couplings is shown. The physical meaning of coupling constants, with particular attention paid to their sign, is discussed. For the case K=2 the interpretation in terms of microscopic interactions between Cooper pairs in different planes, as well as the relation to experimentally measurable quantities, such as the out-of-plane effective mass and bandwidth, is given.

cond-mat.supr-con↗

arXiv2006

Higher grade hybrid model of layered superconductors

A hybrid discrete-continuous model of layered superconductors with interlayer Josephson couplings of arbitrary range is constructed. The conditions required by gauge invariance and thermodynamical stability of the model are determined. Some important special cases, in particular transition to the classic Lawrence-Doniach model, are discussed. The conditions for presence of alternating solutions and the posibilities to describe such states of a superconductor by the continuum or bi-continuum models are examined. The enhancement of superconductivity caused by the presence of higher order Josephson couplings is shown.

cond-mat.supr-con↗

arXiv2002

Bi-continuum modelling of layered structures and crystalline interfaces

The bi-continuum model composed of two interpenetrating and dynamically coupled material continua is analysed as a simplified but relatively accurate way to describe some physical phenomena in crystalline solids. The essential novelty of our approach consists in treating a crystalline medium as bi-continuum, even if the crystalline lattice is structurally single-component. Particular attention is paid to the oscillatory behaviour of solutions on the atomic level. Starting from a discrete atomic chain, the basic formulation of the bi-continuum model is derived. The essential features of the model, including accuracy of the results as functions of physical parameters, are discussed.

cond-mat.mtrl-sci↗