2024/11/22 by Anjana Uday, Gertjan Lippertz, Uday, Anjana +7 · 3 citations
Engineering · Physics and Astronomy · #Advancements in Semiconductor Devices and Circuit Design #FOS: Physical sciences #Magnetic Field Sensors Techniques #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2411.14903
openalex publication_date 2024/11/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Chiral one-dimensional transport can be realized in thin films of a surface-insulating ferromagnetic topological insulator called quantum anomalous Hall insulator (QAHI). When superconducting (SC) pairing correlations are induced in the surface of such a material by putting an s-wave superconductor on the top, the resulting topological superconductivity gives rise to chiral Majorana edge-modes. A quantized two-terminal conductance of (1)/(2)(e2/h) was proposed as a smoking-gun evidence for the topological SC phase associated with a single chiral Majorana edge-mode. There have been experiments to address this proposal, but the conclusion remains unclear. Here, we formulate the edge transport in a multi-terminal superconductor-QAHI heterostructure using the Landauer-Büttiker formalism. Compared to the original proposal for the (1)/(2)(e2/h)-quantization based on a simple two-terminal model, our formalism allows for deeper understanding of the origin of the quantization. The analysis of our experiments on multi-terminal devices unambiguously shows that the half-integer conductance quantization arises from the equilibration of the potentials of the incoming edge states at the SC electrode, and hence it is not of Majorana origin.