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Commensurabilidad de afinación en bicapas retorcidas de van der Waals

Yanxing Li¹, Fan Zhang¹, Viet-Anh Ha^1,2

¹Department of Physics, The University of Texas at Austin, Austin, TX, USA.

|January 17, 2024

Resumen

Las bicapas retorcidas de metales de transición de ángulo grande crean nuevos patrones de moiré, incluidos los cuasicristales y los cristales proporcionales. Estas estructuras exhiben comportamientos electrónicos únicos, abriendo nuevas vías en la física de moiré.

Área de la Ciencia:

Física de la materia condensada
Ciencias de los materiales
Nanotecnología

Sus antecedentes:

Las superredes de Moiré se forman típicamente en bicapas de van der Waals en pequeños ángulos de torsión, lo que resulta en patrones de larga longitud de onda con simetría de traslación aproximada.
En ángulos de giro grandes, los patrones de moiré son generalmente incommensurables, con excepciones en ángulos discretos específicos.

Objetivo del estudio:

Investigar las plataformas distintas que ofrecen las bicapas retorcidas de gran ángulo.
Explorar la creación y las propiedades electrónicas de los patrones de moiré en ángulos de torsión grandes en bicapas de deselenuro de tungsteno.

Principales métodos:

Fabricación de bicapas retorcidas de deselenuro de tungsteno con ángulos de torsión muy grandes.
Utilizó espectroscopia de túnel de barrido con resolución de valle para sondear estructuras electrónicas.

Principales resultados:

Se han creado con éxito dodecágonos cuasicristales incommensurables con un ángulo de torsión de 30°.
Cristales de moiré sintetizados en ángulos de torsión de 21,8° y 38,2°.
Se observaron comportamientos electrónicos distintos entre los cristales de moiré y los cuasicristales, incluida la formación de mini brechas en el valle K cerca del máximo de la banda de valencia.

Conclusiones:

Las bicapas retorcidas de gran ángulo proporcionan una plataforma versátil para generar diversos patrones de moiré, incluidos los cuasicristales.
Estos sistemas exhiben propiedades electrónicas únicas, que difieren significativamente de las estructuras de moiré de ángulo pequeño.
Este trabajo amplía el espacio de diseño para explorar la nueva física moiré más allá de los regímenes tradicionales de ángulo pequeño.

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