Fundamental excitations in layered superconductors with long-range Josephson couplings

TL;DR

This paper extends layered superconductor models to include long-range Josephson couplings and proximity effects, analyzing fundamental excitations and their dispersion relations for various interaction ranges.

Contribution

It introduces a hybrid discrete-continuous model with arbitrary long-range interactions, including proximity effects, and analyzes fundamental excitations within this framework.

Findings

Derived energy formulas for excitations

Analyzed dispersion curve shapes and parameters

Provided expressions for measurable quantities

Abstract

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.