Multiple Topological Phase Transitions Unveiling Gapless Topological Superconductivity in Magnet/Unconventional Superconductor Hybrid Platform

Minakshi Subhadarshini; Amartya Pal; Pritam Chatterjee; Arijit Saha

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arXiv · 2405.01914

Multiple Topological Phase Transitions Unveiling Gapless Topological Superconductivity in Magnet/Unconventional Superconductor Hybrid Platform

Minakshi Subhadarshini·Amartya Pal·Pritam Chatterjee·Arijit Saha

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Abstract

We propose a theoretical framework for generating gapless topological superconductivity (GTSC) hosting Majorana flat edge modes (MFEMs) in the presence of a two-dimensional (2D) array of magnetic adatoms with noncollinear spin texture deposited on top of a unconventional superconductor. Our observations reveal two distinct topological phase transitions within the emergent Shiba band depending on the exchange coupling strength ($J$) between magnetic adatom spins and superconducting electrons: the first one designates transition from gapless non-topological to gapless topological phase at lower $J$, while the second one denotes transition from gapless topological to a trivial gapped superconducting phase at higher $J$. The gapless topological superconducting phase survives at intermediate values of $J$, hosting MFEMs. Further, we investigate the nature of the bulk effective pairings which indicate that GTSC appears due to the interplay between pseudo "$s$-wave" and pseudo "$p_{x}+p_y$" types of pairing. Consequently, our study opens a promising avenue for the experimental realization of GTSC in 2D Shiba lattice based on $d$-wave superconductors as a high-temperature platform.

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Minakshi Subhadarshini, Amartya Pal, Pritam Chatterjee, Arijit Saha. 2024-05-03. Multiple Topological Phase Transitions Unveiling Gapless Topological Superconductivity in Magnet/Unconventional Superconductor Hybrid Platform. https://arxiv.org/abs/2405.01914

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