Microscopic calculation of coherence lengths and magnetic penetration depth in multiband superconductors
Abstract
We present an extended Ginzburg-Landau (GL) method for calculating the superconducting coherence length and magnetic penetration depth at temperatures well below the transition temperature Tc. In contrast to conventional GL theory, which expands the free energy in both the order parameters and their gradients, our method applies a perturbative expansion only to the covariant-gradient terms, while retaining the full dependence on the superconducting order parameters. The coefficients of these terms are determined from finite differences of microscopic free energies evaluated at small imposed pair momenta. The method applies to both single-band and multiband superconductors and therefore provides a framework for incorporating more realistic electronic structures. For the models examined here, the extended GL method agrees well with real-space Bogoliubov-de Gennes (BdG) calculations over a wide temperature range, while requiring substantially less computational effort.
Related
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BibTeX
@misc{fuchs2026microscopic,
title = {{Microscopic calculation of coherence lengths and magnetic penetration depth in multiband superconductors}},
author = {Tristan Ryoma Fuchs and Takuya Nomoto and Hikaru Watanabe and Ryotaro Arita},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.06014},
eprint = {2609.06014},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.06014},
}
RIS
TY - UNPB
TI - Microscopic calculation of coherence lengths and magnetic penetration depth in multiband superconductors
AU - Tristan Ryoma Fuchs
AU - Takuya Nomoto
AU - Hikaru Watanabe
AU - Ryotaro Arita
PY - 2026
DA - 2026/09/05
PB - arXiv
DO - 10.48550/arxiv.2609.06014
UR - https://arxiv.org/abs/2609.06014
AB - We present an extended Ginzburg-Landau (GL) method for calculating the superconducting coherence length and magnetic penetration depth at temperatures well below the transition temperature T_c. In contrast to conventional GL theory, which expands the free energy in both the order parameters and their gradients, our method applies a perturbative expansion only to the covariant-gradient terms, while retaining the full dependence on the superconducting order parameters. The coefficients of these terms are determined from finite differences of microscopic free energies evaluated at small imposed pair momenta. The method applies to both single-band and multiband superconductors and therefore provides a framework for incorporating more realistic electronic structures. For the models examined here, the extended GL method agrees well with real-space Bogoliubov-de Gennes (BdG) calculations over a wide temperature range, while requiring substantially less computational effort.
ER -