Thermodynamic relevance of nanoscale inhomogeneities in Bi2Sr2CaCu2O8+delta

TL;DR

This study uses finite size scaling to analyze specific heat and penetration depth data, revealing nanoscale superconducting grains in Bi2Sr2CaCu2O8+delta, which clarifies the impact of spatial inhomogeneities on its bulk properties.

Contribution

It provides the first estimation of nanoscale grain sizes in Bi2Sr2CaCu2O8+delta, linking microscopic inhomogeneities to thermodynamic behavior.

Findings

Nanoscale superconducting grains are present in Bi2Sr2CaCu2O8+delta.

The grain size is significantly smaller than in other type II superconductors.

Spatial inhomogeneities influence bulk thermodynamic properties.

Abstract

Using finite size scaling we analyze specific heat and London penetration depth data to estimate the spatial extent of the superconducting grains in so called high-quality Bi2Sr2CaCu2O8+delta single crystals. Contrary to the previously investigated type II superconductors, YBa2Cu3O7+delta, MgB2,2H-NbSe2 and Nb77Zr23, where the lower bound for the length scale of the grains ranges from 182 A to 814 A, our analysis uncovers nanoscale superconducting grains. This clarifies the relevance of the spatial variations in the electronic characteristics observed in underdoped Bi2Sr2CaCu2O8+delta with scanning tunnelling microscopy for bulk and thermodynamic properties and establishes their spatial extent.