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Corrientes de borde no topológicas de largo alcance en grafeno neutro de carga
A Aharon-Steinberg1, A Marguerite1, D J Perello2
1Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, Israel.
Nature
|May 27, 2021
Resumen
La no localidad gigante en el grafeno surge de la acumulación de carga en los bordes, creando canales conductores. Este transporte de borde, sensible al desorden, guía las corrientes de largo alcance y explica los fenómenos electrónicos debatidos.
Área de la Ciencia:
- Física de la materia condensada
- Ciencias de los materiales
- Nanotecnología
Sus antecedentes:
- Las heteroestructuras de Van der Waals exhiben propiedades electrónicas únicas, siendo los fenómenos de transporte no locales un área clave de investigación.
- Las mediciones no locales son cruciales para descubrir nuevos mecanismos de transporte como el giro, el valle y las corrientes topológicas en varios materiales 2D.
- El origen de la no localidad gigante, particularmente en el grafeno con neutralidad de carga, sigue siendo un tema de intenso debate científico.
Objetivo del estudio:
- Para investigar la causa subyacente de la no localidad gigante observada en el grafeno.
- Para aclarar el papel de la acumulación de carga de borde en los fenómenos de transporte no locales.
- Comprender la influencia de los campos magnéticos y el desorden de los bordes en el transporte electrónico en el grafeno.
Principales métodos:
- Utilizó un dispositivo de interferencia cuántica superconductor en una punta (SQUID-on-tip) para imágenes térmicas y de escaneo a nanoescala.
- Se han realizado mediciones de transporte no local en muestras de grafeno.
- Analizó el impacto de los campos magnéticos y el desorden de los bordes en el flujo de corriente.
Principales resultados:
- Demostró que la acumulación de carga en los bordes del grafeno crea canales conductores estrechos responsables de la no localidad gigante.
- Se ha observado un desacoplamiento inducido por el campo entre el borde y el transporte de la masa en campos magnéticos moderados.
- Reveló patrones de flujo de carga exóticos sensibles al desorden de los bordes, donde las cargas pueden moverse contra el campo eléctrico.
Conclusiones:
- El transporte de bordes unidimensional, un fenómeno genérico y no topológico, explica la no localidad gigante en el grafeno.
- Este transporte guiado por el borde se espera en muchos sistemas electrónicos, ofreciendo información sobre mecanismos de transporte controvertidos.
- Los hallazgos vinculan los fenómenos de transporte no locales con los estados electrónicos de largo alcance localizados en los bordes del sistema.
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