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Efecto Hall anómalo cuántico de las bandas de moiré entrelazadas
Tingxin Li1,2, Shengwei Jiang1,2, Bowen Shen1
1School of Applied and Engineering Physics and Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY, USA.
Nature
|December 23, 2021
Resumen
Los investigadores observaron un efecto Hall anómalo cuántico en los materiales moiré semiconductores. Un campo eléctrico sintonizó la topología y la correlación, lo que condujo a una nueva transición de fase topológica sin cerrar la brecha de carga masiva.
Área de la Ciencia:
- Física de la materia condensada
- Física de los semiconductores
- Ciencias de los materiales
Sus antecedentes:
- La correlación de electrones y la topología de bandas son áreas clave en la física moderna.
- Los materiales semiconductores moiré ofrecen una plataforma sintonizable para el estudio de los fenómenos de correlación de electrones.
- La topología de banda no trivial en estos sistemas sigue siendo en gran medida inexplorada.
Objetivo del estudio:
- Investigar la interacción de la correlación de electrones y la topología de la banda en los materiales moiré semiconductores.
- Para explorar la posibilidad de observar fenómenos topológicos como el efecto Hall anómalo cuántico.
- Comprender las transiciones de fase topológicas inducidas por el campo eléctrico.
Principales métodos:
- Fabricación y caracterización de los heterobilayers MoTe2/WSe2 apilados en AB.
- Aplicación de campos eléctricos fuera del plano para ajustar las propiedades del material.
- Medición de la resistencia de Hall y de la resistencia longitudinal en condiciones variables.
Principales resultados:
- Observación del efecto Hall anómalo cuántico (resistencia de Hall cuantizada h/e^2) en heterobilares moiré MoTe2/WSe2 apilados en AB.
- Demostración de que los campos eléctricos controlan tanto el ancho de banda como la topología de banda.
- Identificación de una transición de fase topológica inducida por el campo eléctrico del aislante Mott al aislante Hall anómalo cuántico, que precede a una transición de aislante a metal sin cierre de la brecha de carga a granel.
Conclusiones:
- Las heterobilas de moiré de semiconductores son plataformas prometedoras para explorar estados topológicos correlacionados.
- La topología de banda ajustable de campo eléctrico ofrece nuevas vías para controlar los fenómenos cuánticos.
- El mecanismo de transición de fase observado proporciona información sobre nuevos fenómenos topológicos impulsados por la correlación y la topología.
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