Scaling of NonOhmic Conduction in Strongly Correlated Systems

TL;DR

This paper introduces a new scaling formalism to analyze nonlinear I-V data near metal-insulator transitions in manganites, revealing universal behaviors and characteristic exponents related to non-Ohmic conduction in strongly correlated systems.

Contribution

It develops a novel scaling approach to characterize non-Ohmic conduction and identifies a universal response in disordered manganite systems near MIT.

Findings

Onset field for nonlinearity is anomalously low, supporting electronically soft phases.

Scaling functions are consistent above and below MIT but have different exponents.

The scaling formalism applies universally to disordered manganites, indicating a common response to electric fields.

Abstract

A new scaling formalism is used to analyze nonlinear I-V data in the vicinity of metal-insulator transitions (MIT) in five manganite systems. An exponent, called the nonlinearity exponent, and an onset field for nonlinearity, both characteristic of the system under study, are obtained from the analysis. The onset field is found to have an anomalously low value corroborating the theoretically predicted electronically soft phases. The scaling functions above and below the MIT of a polycrystalline sample are found to be the same but with different exponents which are attributed to the distribution of the MIT temperatures. The applicability of the scaling in manganites underlines the universal response of the disordered systems to electric field.