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Superconductividad e interacciones fuertes en un cuasicristal de moiré sintonizable
Aviram Uri1, Sergio C de la Barrera2, Mallika T Randeria3
1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. aviramu@mit.edu.
Nature
|July 19, 2023
Resumen
Los investigadores crearon un casi cristal de moiré sintonizable a partir de capas de grafeno. Este nuevo material cuántico exhibe superconductividad y ofrece información sobre los estados electrónicos cuasicristalinos que interactúan fuertemente.
Área de la Ciencia:
- Física de la materia condensada
- Ciencias de los materiales
- Los materiales cuánticos
Sus antecedentes:
- Los cuasicristales poseen propiedades electrónicas únicas que se desvían de la descripción de Bloch, lo que los hace complejos y menos explorados que los materiales periódicos o amorfos.
- Los cuasicristales existentes a menudo son escasos y difíciles de diseñar, lo que limita los estudios detallados de su comportamiento electrónico.
Objetivo del estudio:
- Introducir un nuevo sistema de cuasi-cristal altamente sintonizable montado a partir de componentes periódicos fácilmente disponibles.
- Investigar las propiedades electrónicas y los fenómenos emergentes, como la superconductividad, en cuasicristales diseñados.
Principales métodos:
- Fabricación de un "cuasicristal de moiré" mediante el apilamiento de tres capas de grafeno con dos ángulos de giro distintos, creando patrones de moiré inconmensurables.
- Ajuste del potencial químico del sistema electrónico para la transición entre regímenes similares a los periódicos y fuertemente cuasiperiódicos.
- Observación de estados electrónicos y transiciones de fase mediante mediciones de transporte.
Principales resultados:
- El cuasicristal moiré exhibe cuasiperiodicidad en escalas de longitud nanométricas, ajustable desde un régimen electrónico similar a un régimen electrónico fuertemente cuasiperiódico.
- Se observó una alta densidad de estados electrónicos de dispersión débil en el régimen cuasiperiódico.
- Se detectó superconductividad cerca de una transición de fase de ruptura de simetría de sabor, destacando el papel de las interacciones electrónicas.
Conclusiones:
- El cuasicristal de moiré diseñado proporciona una plataforma versátil para estudiar sistemas electrónicos e interacciones cuasiperiódicas.
- Este sistema ofrece nuevas vías para explorar fenómenos cuánticos en cuasicristales sintonizables y materiales moiré relacionados.
- Un mayor desarrollo de esta plataforma podría conducir a nuevos materiales cuánticos para investigar cuasicristales fuertemente interactuantes.
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