# Comment on arXiv:1807.08572: a plausible explanation of the giant diamagnetism found in Au-Ag nanostructures

## TL;DR

This paper proposes that the giant diamagnetism observed in Au-Ag nanostructures may result from quantum confinement effects causing a gapped electronic spectrum, which suppresses scattering and enhances diamagnetic response.

## Contribution

It introduces a plausible explanation linking quantum confinement-induced energy gaps to the observed giant diamagnetism in nanostructures.

## Key findings

- Gapped electronic spectrum due to quantum confinement.
- Suppressed electronic scattering enhances diamagnetism.
- Provides a non-superconducting explanation for diamagnetic behavior.

## Abstract

In a recent comment (arXiv:1906.05742) on the preprint (arXiv:1807.08572) entitled "Coexistence of Diamagnetism and Vanishingly Small Electrical Resistance at Ambient Temperature and Pressure in Nanostructures", it is pointed out that the reduction of the four-probe resistance ($R_{4P}$) to zero value is accompanied by a rise in the two probe resistance ($R_{2P}$) in the same temperature range. This curious correlation between $R_{4P}$ and $R_{2P}$ is said to be pointing towards a non-superconducting "conductance percolation" transition (rather than "percolating superconducting transition" as proposed in the revised version of arxiv:1807.08572). The explanation offered in preprint arXiv:1906.05742 is quite reasonable, but the author leaves open the question of giant diamagnetism. In this short comment I suggest a plausible cause of the giant diamagnetism found in nanostructures. It could be due to gapped electronic energy spectrum of nanoparticles which is due to quantum confinement effects, and that suppresses the electronic scattering mechanism leading to a very high value of Langevin diamagnetism.