Details

Autor(en) / Beteiligte

• Kayyalha, Morteza
• Xiao, Di
• Zhang, Ruoxi
• Shin, Jaeho
• Jiang, Jue
• Wang, Fei
• Zhao, Yi-Fan
• Xiao, Run
• Zhang, Ling
• Fijalkowski, Kajetan M
• Mandal, Pankaj
• Winnerlein, Martin
• Gould, Charles
• Li, Qi
• Molenkamp, Laurens W
• Chan, Moses H W
• Samarth, Nitin
• Chang, Cui-Zu

Titel

Absence of evidence for chiral Majorana modes in quantum anomalous Hall-superconductor devices

Ist Teil von

• Science (American Association for the Advancement of Science), 2020-01, Vol.367 (6473), p.64-67

Ort / Verlag

United States: The American Association for the Advancement of Science

Erscheinungsjahr

2020

Quelle

Science Magazine

Beschreibungen/Notizen

• A quantum anomalous Hall (QAH) insulator coupled to an s-wave superconductor is predicted to harbor chiral Majorana modes. A recent experiment interprets the half-quantized two-terminal conductance plateau as evidence for these modes in a millimeter-size QAH-niobium hybrid device. However, non-Majorana mechanisms can also generate similar signatures, especially in disordered samples. Here, we studied similar hybrid devices with a well-controlled and transparent interface between the superconductor and the QAH insulator. When the devices are in the QAH state with well-aligned magnetization, the two-terminal conductance is always half-quantized. Our experiment provides a comprehensive understanding of the superconducting proximity effect observed in QAH-superconductor hybrid devices and shows that the half-quantized conductance plateau is unlikely to be induced by chiral Majorana fermions in samples with a highly transparent interface.