# Size-effect of Kondo scattering in point contacts (revisited)

## TL;DR

This study investigates how the Kondo effect varies with size in nanometer-scale metallic point contacts, revealing that smaller contacts (<10 nm) exhibit enhanced Kondo resonance effects, especially in clean, channel-shaped contacts.

## Contribution

It provides new experimental insights into the size-dependent behavior of Kondo scattering in nanostructures, specifically in clean, channel-shaped CuMn alloy contacts.

## Key findings

- Kondo resonance width increases in contacts smaller than 10 nm
- Enhanced ratio of Kondo peak to electron-phonon scattering in small contacts
- Size effect observed predominantly in clean, channel-shaped contacts

## Abstract

The size-effect of Kondo-scattering in nanometer-sized metallic point contacts is measured with the simplified, mechanically-controlled break-junction technique for CuMn alloy of different Mn concentrations: 0.017; 0.035; and 0.18 ($\pm$0.017) at.\%. The results are compared with our previous publication on nominally 0.1 at.\% CuMn alloy \cite{1,2}. The increase of width of the Kondo resonance and enhanced ratio of Kondo-peak intensity to electron-phonon scattering intensity is observed for contacts with sizes smaller than 10 $nm$. From the comparison of electron-phonon scattering intensity for the pressure-type contacts, which correspond to the clean orifice model, we conclude that the size effect is observed in \emph{clean} contacts with the shape of a \emph{channel} (nanowire).