Intra-unit-cell singlet pairing mediated by altermagnetic fluctuations

Fuente: arXiv
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Main Authors: Wu, Yi-Ming, Wang, Yuxuan, Fernandes, Rafael M.
Format: Preprint
Published: 2025
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author Wu, Yi-Ming
Wang, Yuxuan
Fernandes, Rafael M.
author_facet Wu, Yi-Ming
Wang, Yuxuan
Fernandes, Rafael M.
contents We investigate the superconducting instabilities induced by altermagnetic fluctuations. Because of the non-trivial sublattice structure of the altermagnetic order, shorter-range and longer-range fluctuations favor qualitatively different types of pairing states. Specifically, while the latter stabilize a standard spin-triplet $p$-wave state, just like ferromagnetic fluctuations, the former leads to intra-unit-cell pairing, in which the Cooper pairs are formed by electrons from different sublattices. The symmetry of the intra-unit-cell gap function can be not only $p$-wave, but also spin-singlet $s$-wave and $d$-wave, depending on the shape of the Fermi surface. We also show that coexistence with altermagnetic order promotes intrinsic non-trivial topology, such as protected Bogoliubov Fermi surfaces and higher-order topological superconductivity. Our work establishes the key role played by sublattice degrees of freedom in altermagnetic-fluctuation mediated interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2506_04356
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Intra-unit-cell singlet pairing mediated by altermagnetic fluctuations
Wu, Yi-Ming
Wang, Yuxuan
Fernandes, Rafael M.
Superconductivity
We investigate the superconducting instabilities induced by altermagnetic fluctuations. Because of the non-trivial sublattice structure of the altermagnetic order, shorter-range and longer-range fluctuations favor qualitatively different types of pairing states. Specifically, while the latter stabilize a standard spin-triplet $p$-wave state, just like ferromagnetic fluctuations, the former leads to intra-unit-cell pairing, in which the Cooper pairs are formed by electrons from different sublattices. The symmetry of the intra-unit-cell gap function can be not only $p$-wave, but also spin-singlet $s$-wave and $d$-wave, depending on the shape of the Fermi surface. We also show that coexistence with altermagnetic order promotes intrinsic non-trivial topology, such as protected Bogoliubov Fermi surfaces and higher-order topological superconductivity. Our work establishes the key role played by sublattice degrees of freedom in altermagnetic-fluctuation mediated interactions.
title Intra-unit-cell singlet pairing mediated by altermagnetic fluctuations
topic Superconductivity
url https://arxiv.org/abs/2506.04356