Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography

TL;DR

This paper predicts that electron holography measurements will show an apparent increase in superconducting particle thickness at low temperatures due to changes in the mean inner potential caused by electronic wavefunction expansion and charge expulsion, providing insights into superconducting physics.

Contribution

It introduces a theoretical prediction that electron holography can detect electronic structure changes in superconductors through apparent thickness variations.

Findings

Predicted apparent thickness increase at low temperatures.

Linked phase shift changes to electronic wavefunction expansion.

Suggests phase shift measurements reveal superconducting state physics.

Abstract

We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals.