Oscillatory magnetic field-dependent critical temperatures of ultraclean Type-II superconductors

Fuente: arXiv
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Main Authors: Zhao, Aiying, Klemm, Richard A, Gu, Qiang
Format: Preprint
Published: 2024
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author Zhao, Aiying
Klemm, Richard A
Gu, Qiang
author_facet Zhao, Aiying
Klemm, Richard A
Gu, Qiang
contents The influence of the Zeeman energy and the Landau levels (LLs) arising from an applied magnetic field ${\bf B}$ upon the critical temperature $T_c$ is studied using a fully quantum mechanical method within the framework of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity that forms from an ultraclean metal. As in semiclassical treatments, we found that two electrons can form Cooper pairs with opposite spins and momenta in the ${\bf B}$ direction while either in the same or in neighboring LLs. However, the fully quantum mechanical treatment of the LLs causes $T_c({\bf B})$ for electrons paired on the same LL to oscillate about the critical temperature of the BCS theory, similar to that of the de Haas-van Alphen effect. The Zeeman energy causes $T_c({\bf B})$ to decrease in an oscillatory fashion with increasing ${\bf B}$ for electrons paired either on the same or on neighboring LLs. For the Zeeman $g > 1$, pairing on neighboring LLs results in the highest $T_c({\bf B})$. For $g < 1$, pairing on the same LLs gives the highest $T_c({\bf B})$. In addition, $T_c({\bf B})$ for electrons paired on neighboring LLs exhibits an apparent symmetry around $g=2$, as the oscillatory critical temperature behaviors are nearly identical for $g=2\pmδ$.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05111
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Oscillatory magnetic field-dependent critical temperatures of ultraclean Type-II superconductors
Zhao, Aiying
Klemm, Richard A
Gu, Qiang
Superconductivity
Mesoscale and Nanoscale Physics
The influence of the Zeeman energy and the Landau levels (LLs) arising from an applied magnetic field ${\bf B}$ upon the critical temperature $T_c$ is studied using a fully quantum mechanical method within the framework of the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity that forms from an ultraclean metal. As in semiclassical treatments, we found that two electrons can form Cooper pairs with opposite spins and momenta in the ${\bf B}$ direction while either in the same or in neighboring LLs. However, the fully quantum mechanical treatment of the LLs causes $T_c({\bf B})$ for electrons paired on the same LL to oscillate about the critical temperature of the BCS theory, similar to that of the de Haas-van Alphen effect. The Zeeman energy causes $T_c({\bf B})$ to decrease in an oscillatory fashion with increasing ${\bf B}$ for electrons paired either on the same or on neighboring LLs. For the Zeeman $g > 1$, pairing on neighboring LLs results in the highest $T_c({\bf B})$. For $g < 1$, pairing on the same LLs gives the highest $T_c({\bf B})$. In addition, $T_c({\bf B})$ for electrons paired on neighboring LLs exhibits an apparent symmetry around $g=2$, as the oscillatory critical temperature behaviors are nearly identical for $g=2\pmδ$.
title Oscillatory magnetic field-dependent critical temperatures of ultraclean Type-II superconductors
topic Superconductivity
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2412.05111