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Destrucción de la coherencia de fase global en cilindros superconductores ultradelgados y doblemente conectados
Y Liu1, Y Zadorozhny, M M Rosario
1Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA. liu@phys.psu.edu
Science (New York, N.Y.)
|December 18, 2001
Resumen
La velocidad del superfluido en los superconductores huecos aumenta con tamaños de muestra más pequeños, lo que lleva a la destrucción de la superconductividad. Este estudio revela regiones coherentes de fase desconectadas en cilindros ultrafinos, a diferencia de los más grandes.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- La superconductividad es la superconductividad.
- Los fenómenos cuánticos son fenómenos cuánticos.
Sus antecedentes:
- Los superconductores doblemente conectados exhiben fluidos cuantificados, lo que permite el control de la velocidad del superfluido a través del flujo magnético y el tamaño de la muestra.
- Las predicciones teóricas sugieren que el aumento de la velocidad superfluida en muestras más pequeñas puede destruir la superconductividad cerca de los cuantos de flujo de medio entero.
Objetivo del estudio:
- Para verificar experimentalmente el régimen destructivo predicho de superconductividad en cilindros huecos ultrafinos.
- Investigar el papel del tamaño de la muestra en el control de la velocidad del superfluido y la coherencia de fase.
- Para caracterizar el diagrama de fase de la superconductividad en cilindros ultrafinos.
Principales métodos:
- Las mediciones de transporte se llevaron a cabo en cilindros huecos ultradelgados de aluminio (Al) y oro-indio (Au0.7In0.3).
- El flujo magnético aplicado y las dimensiones de la muestra se variaron sistemáticamente.
- La coherencia de fase global fue monitoreada a través de las propiedades de transporte eléctrico.
Principales resultados:
- La evidencia experimental confirma un régimen destructivo para la superconductividad en cilindros ultrafinos, vinculado a la pérdida de la coherencia de fase global.
- El fenómeno observado ocurre alrededor de cuantos de flujo de medio entero, consistente con las predicciones teóricas.
- Se reveló un nuevo diagrama de fase, con regiones coherentes de fase desconectadas, que difieren de los cilindros superconductores más grandes.
Conclusiones:
- Los superconductores huecos ultrafinos exhiben propiedades superconductoras únicas distintas de sus contrapartes más grandes.
- El tamaño de la muestra es un parámetro crítico que influye en la velocidad del superfluido y la estabilidad de la superconductividad.
- Los hallazgos proporcionan nuevos conocimientos sobre los mecanismos fundamentales que rigen la superconductividad en sistemas mesoscópicos.
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