A plausible explanation of the repeated "noise" pattern in the data of arXiv:1807.08572: quantum confinement and surface phonon modes

TL;DR

The paper proposes that the temperature-dependent 'noise' pattern observed in a specific experiment is caused by elasto-magnetic coupling involving surface phonon modes and surface currents, which are discretely excited due to quantum confinement effects.

Contribution

It introduces a novel explanation linking quantum confinement, surface phonon modes, and elasto-magnetic coupling to the observed noise pattern in susceptibility data.

Findings

Noise pattern varies with temperature due to phonon mode excitation.

Discrete phonon modes modulate surface currents, causing magnetization fluctuations.

Quantum confinement leads to discrete phonon energies in nanoparticles.

Abstract

A key point from the experiment related to the "noise" pattern in figure 3(a) of arXive:1807.08572 is that it is a function of temperature. We put forward a possible explanation. We argue that it is the elasto-magnetic coupling in which the diamagnetic surface currents on the surface of nanoparticles couple to surface phonon modes. As the temperature is increased (say from 210 K to 220 K), successive phonon modes are excited, one by one. This is due to quantum confinement where phonon modes take discrete values of energy (in bulk, the modes are quasi-continuous). One by one excitation of phonon modes modulates the surface currents on nano-particles that led to a fluctuating magnetization thus "noise" in the lower part of the susceptibility data where the system is in the superconducting state.