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Un pico agudo de la profundidad de penetración a temperatura cero en la composición óptima en BaFe2(As(1-x) P(x)) 2
K Hashimoto1, K Cho, T Shibauchi
1Department of Physics, Kyoto University, Kyoto, Japan.
Science (New York, N.Y.)
|June 23, 2012
Resumen
Los investigadores encontraron un pico en la profundidad de penetración de Londres en los superconductores BaFe(2)(As(1)(-x)P(x))(2) con una composición óptima. Esto sugiere que las fluctuaciones cuánticas cerca de un punto crítico cuántico pueden conducir a un cruce hacia la condensación Bose-Einstein.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Investigación de la superconductividad Investigación de la superconductividad
Sus antecedentes:
- La relación entre la densidad de la portadora (n) y la masa efectiva (m*) en los superconductores dicta la profundidad de penetración de Londres (λ(L), un indicador clave de la longitud de flujo del superfluido.
- En los sistemas 2D, n/m* (~1/λ) es crucial para determinar la temperatura efectiva de Fermi (T).
Objetivo del estudio:
- Para investigar el comportamiento de la profundidad de penetración de Londres (λ(L)) en los superconductores BaFe(2)(As(1)(-x)P(x))(2).
- Para explorar la relación entre λ(L), las fluctuaciones cuánticas y la temperatura de transición superconductora (T(c)) en diferentes composiciones.
Principales métodos:
- Medición experimental de la profundidad de penetración de Londres (λ(L)) en función de la composición (x) en muestras limpias de BaFe(2)(As(1)(-x)P(x)))) a temperatura cero.
- Análisis de la temperatura de transición superconductora (T ((c)) y la temperatura efectiva de Fermi (T ((F)) en la composición óptima.
Principales resultados:
- Se observó un fuerte pico en λ (L) (x) a temperatura cero para BaFe (As) (x) en la composición óptima x = 0,30.
- La temperatura máxima de transición superconductora (T ((c)) alcanzó los 30 Kelvin en x = 0,30.
- Se encontró una relación mejorada de T (c) / T (F) en x = 0.30.
Conclusiones:
- El pico observado λ (L) sugiere la influencia de las fluctuaciones cuánticas, potencialmente vinculadas a un punto crítico cuántico en el material.
- La relación T (c) /T (F) mejorada indica un posible cambio hacia el límite de condensado de Bose-Einstein, impulsado por la criticidad cuántica.
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