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El estado fundamental del pseudogap en los superconductores de cuprato
T Valla1, A V Fedorov, Jinho Lee
1Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA. valla@bnl.gov
Science (New York, N.Y.)
|November 18, 2006
Resumen
La superconductividad en La(2-x) BaxCuO4 se suprime por orden de carga de giro. Incluso sin superconductividad, persiste una brecha de energía, lo que sugiere un estado de onda d incoherente en fase con pares de Cooper formando estructuras ordenadas.
Área de la Ciencia:
- Física de la materia condensada Física de la materia condensada
- Ciencia de los materiales Ciencia de los materiales.
- La superconductividad es la superconductividad.
Sus antecedentes:
- La(2-x) BaxCuO4 exhibe superconductividad sensible a los niveles de dopaje.
- Las órdenes estáticas de espín y carga, conocidas como "rayas", emergen cerca de x = 1/8, suprimiendo la superconductividad.
Objetivo del estudio:
- Investigar la estructura electrónica de La(2-x) BaxCuO4 en el nivel de dopaje x = 1/8.
- Determinar la naturaleza del estado electrónico cuando la superconductividad es suprimida por la formación de rayas.
Principales métodos:
- Espectroscopia de fotoemisión con resolución de ángulo (ARPES)
- Microscopía de túnel de barrido (STM, por sus siglas en inglés)
Principales resultados:
- Se detectó una brecha de energía en la superficie de Fermi.
- La magnitud de la brecha y la densidad lineal de los estados son consistentes con la simetría de onda d.
- La brecha persiste incluso cuando la superconductividad desaparece en x = 1/8, con nodos en cuatro puntos.
Conclusiones:
- El estado no superconductor en x = 1/8 es un superconductor de onda d incoherente en fase.
- Las parejas Cooper en este estado forman estructuras ordenadas por carga de espín en lugar de lograr superconductividad.
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