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Pruebas de la anomalía quiral en el semimetal Dirac Na3Bi
Jun Xiong1, Satya K Kushwaha2, Tian Liang1
1Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Science (New York, N.Y.)
|September 5, 2015
Resumen
Los investigadores observaron magnetorresistencia negativa en Na3Bi, un semimetal de Dirac. Este efecto, vinculado a la anomalía quiral, demuestra el flujo de carga entre los nodos de Weyl bajo campos eléctricos y magnéticos paralelos.
Área de la Ciencia:
- Física de la materia condensada
- Teoría del campo cuántico
Sus antecedentes:
- Los semimetales de Dirac presentan nodos de Dirac que se dividen en pares de nodos de Weyl con una quiralidad distinta.
- Estas poblaciones quirales normalmente no interactúan ni se mezclan.
- La anomalía quiral predice el flujo de carga entre los nodos de Weyl en campos eléctricos y magnéticos paralelos.
Objetivo del estudio:
- Observar y caracterizar experimentalmente la anomalía quiral en un semimetal de Dirac.
- Para investigar la magnetorresistencia negativa prevista que surge del flujo de carga axial.
Principales métodos:
- Observación experimental de la magnetorresistencia longitudinal en el semimetal Dirac Na3Bi.
- Variación sistemática de las orientaciones de los campos eléctrico y magnético.
- Análisis de la sensibilidad de la magnetorresistencia a la desalineación del campo.
Principales resultados:
- Se observó una gran magnetorresistencia longitudinal negativa en el Na3Bi.
- El efecto observado mostró una sensibilidad aguda a la alineación de los campos eléctricos y magnéticos.
- Los resultados experimentales fueron inconsistentes con los fenómenos de transporte convencionales.
Conclusiones:
- Los hallazgos proporcionan una fuerte evidencia de la anomalía quiral en un sistema de estado sólido.
- La magnetorresistencia negativa observada es consistente con el transporte de carga entre los nodos de Weyl según lo predicho por la teoría.
- Este estudio valida la anomalía de Adler-Bell-Jackiw en el contexto de los semimetales de Dirac.
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