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arXiv · 2209.14885

Majorana corner modes and flat-band Majorana edge modes in superconductor/topological-insulator/superconductor junctions

Xiao-Ting Chen·Chun-Hui Liu·Dong-Hui Xu·Chui-Zhen Chen
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Abstract

Recently, superconductors with higher-order topology have stimulated extensive attention and research interest. Higher-order topological superconductors exhibit unconventional bulk-boundary correspondence, thus allow exotic lower-dimensional boundary modes, such as Majorana corner and hinge modes. However, higher-order topological superconductivity has yet to be found in naturally occurring materials. In this work, we investigate higher-order topology in a two-dimensional Josephson junction comprised of two $s$-wave superconductors separated by a topological insulator thin film. We found that zero-energy Majorana corner modes, a boundary fingerprint of higher-order topological superconductivity, can be achieved by applying magnetic field. When an in-plane Zeeman field is applied to the system, two corner states appear in the superconducting junction. Furthermore, we also discover a two dimensional nodal superconducting phase which supports flat-band Majorana edge modes connecting the bulk nodes. Importantly, we demonstrate that zero-energy Majorana corner modes are stable when increasing the thickness of topological insulator thin film.

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Xiao-Ting Chen, Chun-Hui Liu, Dong-Hui Xu, Chui-Zhen Chen. 2022-09-29. Majorana corner modes and flat-band Majorana edge modes in superconductor/topological-insulator/superconductor junctions. https://doi.org/10.1088/0256-307x%2F40%2F9%2F097403

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