Heat Capacity of Mesoscopic Superconducting Disks

TL;DR

This paper investigates how the heat capacity of mesoscopic superconducting disks varies with magnetic field and vortex states, revealing size effects and connections to the paramagnetic Meissner effect.

Contribution

It provides a theoretical analysis of heat capacity behavior in mesoscopic superconductors across different vortex states using Ginzburg-Landau theory.

Findings

Heat capacity discontinuity at $T_c$ diminishes with increasing field for $L=0$.

Higher $L$ states exhibit continuous heat capacity changes at $T_c$.

Peak position behavior relates to the paramagnetic Meissner effect and positive magnetization.

Abstract

We study the heat capacity of isolated giant vortex states, which are good angular momentum ($L$) states, in a mesoscopic superconducting disk using the Ginzburg-Landau (GL) theory. At small magnetic fields the $L$=0 state qualitatively behaves like the bulk sample characterized by a discontinuity in heat capacity at $T_c$. As the field is increased the discontinuity slowly turns into a continuous change which is a finite size effect. The higher $L$ states show a continuous change in heat capacity at $T_c$ at all fields. We also show that for these higher $L$ states, the behavior of the peak position with change in field is related to the paramagnetic Meissner effect (irreversible) and can lead to an unambiguous observation of positive magnetization in mesoscopic superconductors.