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Resonancia de las fluctuaciones de espín antiferromagnético para la superconductividad en UTe2
Chunruo Duan1, R E Baumbach2,3, Andrey Podlesnyak4
1Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, USA.
Nature
|December 23, 2021
Resumen
La superconductividad en UTe2 está vinculada a una excitación magnética, lo que sugiere que las fluctuaciones de espín antiferromagnético pueden inducir el emparejamiento de espín triplet o indicar un componente de espín singlet en este superconductor topológico.
Área de la Ciencia:
- Física de la materia condensada
- Ciencias de los materiales
- Los materiales cuánticos
Sus antecedentes:
- La superconductividad surge de pares de electrones Cooper que se mueven sin resistencia por debajo de una temperatura crítica (Tc).
- La mayoría de los superconductores exhiben pares de Cooper de spin-singlet (S=0), pero el emparejamiento de spin-triplet (S=1) es crucial para los estados topológicos y la computación cuántica.
- Los materiales basados en uranio cerca de la inestabilidad ferromagnética (FM) son los principales candidatos para la superconductividad de espín triple, con UTe2 identificado como un potencial superconductor topológico quiral de espín triple.
Objetivo del estudio:
- Para investigar las excitaciones magnéticas acopladas a la superconductividad en UTe2.
- Determinar el papel de las fluctuaciones de espín (FM y antiferromagnético (AF)) en la superconductividad no convencional de UTe2.
- Explorar el mecanismo de emparejamiento en UTe2, específicamente si involucra pares de Cooper de espín triple o espín singlete.
Principales métodos:
- Se empleó dispersión de neutrones inelástica (INS) para sondear excitaciones magnéticas en UTe2.
- El estudio se centró en las excitaciones magnéticas en el límite de la zona de Brillouin cerca del orden antiferromagnético.
- Se realizó un análisis de la excitación magnética observada, denominada resonancia.
Principales resultados:
- Se observó una aguda excitación magnética, una resonancia, en UTe2 junto con su superconductividad.
- Esta resonancia fue encontrada en el límite de la zona de Brillouin cerca del orden antiferromagnético.
- La presencia de esta resonancia, típicamente vista en superconductores de spin-singlet cerca de la inestabilidad AF, fue inesperada en UTe2.
Conclusiones:
- La observación de la resonancia en UTe2 sugiere que las fluctuaciones del espín antiferromagnético podrían inducir el emparejamiento del espín triple.
- Alternativamente, los hallazgos indican que el emparejamiento de electrones en UTe2 podría poseer un componente de spin-singlet.
- Este descubrimiento desafía los paradigmas existentes y abre nuevas vías para comprender la superconductividad no convencional y los materiales topológicos.
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