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Las firmas de superconductividad quiral en grafeno romboédrico

Tonghang Han¹, Zhengguang Lu^1,2, Zach Hadjri¹

¹Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.

|May 22, 2025

Resumen

Los investigadores descubrieron la superconductividad quiral en el grafeno puro, un avance para la física topológica y la computación cuántica. Este hallazgo abre nuevas vías para explorar los fermiones de Majorana y construir computadoras cuánticas tolerantes a fallos.

Área de la Ciencia:

Física de la materia condensada
Ciencias de los materiales
La computación cuántica

Sus antecedentes:

Los superconductores quirales rompen la simetría de inversión de tiempo y pueden albergar fermiones de Majorana, cruciales para la física topológica y la computación cuántica.
A pesar de la extensa investigación, el descubrimiento definitivo de la superconductividad quiral ha permanecido elusivo en los sistemas candidatos.

Objetivo del estudio:

Para informar sobre el descubrimiento de una robusta superconductividad no convencional en el grafeno romboédrico de cuatro y cinco capas.
Investigar las propiedades y aplicaciones potenciales de estos nuevos estados superconductores.

Principales métodos:

Fabricación y caracterización de dispositivos de grafeno mediante puertas electrostáticas.
Medición de la resistencia eléctrica (Rxx) y del efecto Hall bajo campos magnéticos variables (fuera del plano y dentro del plano).
Análisis de las temperaturas de transición superconductoras (Tc) y de las densidades del portador de carga (ne).

Principales resultados:

Descubrimiento de dos estados superconductores robustos en el grafeno de tetra capa y penta capa con Tc de hasta 300 mK.
Observación de la ruptura de simetría espontánea de inversión del tiempo (TRSB) y las características quirales, incluida la histeresis magnética en Rxx.
Los estados superconductores son robustos contra los campos magnéticos en el plano y emergen de una fase de cuarto de metal polarizada por espín y valle.

Conclusiones:

El grafeno se establece como una plataforma de material de carbono puro para el estudio de la superconductividad topológica.
Los hallazgos allanan el camino para explorar los modos de Majorana y avanzar en la computación cuántica topológica.
La superconductividad de acoplamiento fuerte observada se acerca al cruce BCS-BEC.

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