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Conductividad térmica del volumen cuántico de Hall
Ron Aharon Melcer1,2, Avigail Gil2, Arup Kumar Paul1,2
1Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
Nature
|January 3, 2024
Resumen
Los estados localizados en el efecto Hall cuántico conducen el calor de manera eficiente, incluso cuando el material es eléctricamente aislante. Este estudio revela su papel crucial en el transporte térmico, ofreciendo nuevos conocimientos sobre la materia topológica.
Área de la Ciencia:
- Física de la materia condensada
- Materia topológica
- El efecto Hall cuántico
Sus antecedentes:
- El efecto Hall cuántico (QHE) es un ejemplo clave de los estados topológicos de la materia, que surgen de interacciones complejas y desorden.
- El desorden crea estados localizados en la mayor parte, cruciales para estabilizar los estados QHE, pero difíciles de estudiar experimentalmente.
- Comprender las propiedades de transporte de estos estados localizados es esencial para el avance de la física topológica.
Objetivo del estudio:
- Investigar las propiedades de transporte térmico de los estados localizados en la mayor parte de los sistemas cuánticos Hall.
- Para separar experimentalmente la conductividad térmica a granel de las contribuciones de borde en un dispositivo microfabricado.
- Para aclarar el papel de los estados localizados en la conducción de calor dentro de los aislantes topológicos.
Principales métodos:
- Se utilizó un nuevo dispositivo corto "multiterminal" con una escala de 10 μm para mediciones precisas.
- Conductividad térmica longitudinal separada (contribución de volumen) de la conductividad térmica transversal (contribución de borde).
- Variaciones de conductividad térmica analizadas con ajuste de campo magnético, particularmente lejos de los centros de las mesetas de conductividad.
Principales resultados:
- Demostró que los estados localizados en el bulto conducen el calor de manera eficiente ([Formula: ver texto]) mientras que el bulto permanece eléctricamente aislante.
- Conductividad térmica finita observada ([Fórmula: ver texto]) a través de mesetas para estados fraccionarios (por ejemplo, [Fórmula: ver texto], [Fórmula: ver texto]) en el primer nivel de Landau excitado.
- Mostró una eficiente conducción de calor a través de estados localizados cuando el campo magnético está sintonizado lejos del centro de la meseta.
Conclusiones:
- Los estados localizados en la masa del efecto Hall cuántico son conductores de calor eficientes.
- El estudio proporciona pruebas experimentales del papel significativo de los estados localizados a granel en el transporte térmico.
- Un modelo teórico apoya los hallazgos, identificando estados localizados como el origen de la conductividad térmica finita.
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