Engineering second order topological superconductor hosting tunable Majorana corner modes in magnet/$d$-wave superconductor hybrid platform

Fuente: arXiv
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Autori principali: Subhadarshini, Minakshi, Mishra, Archana, Saha, Arijit
Natura: Preprint
Pubblicazione: 2025
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author Subhadarshini, Minakshi
Mishra, Archana
Saha, Arijit
author_facet Subhadarshini, Minakshi
Mishra, Archana
Saha, Arijit
contents We theoretically study the noncollinear magnetic texture effect on second-order topological superconductor (SOTSC) phase generated in unconventional $d$-wave superconductors and two-dimensional (2D) quantum spin Hall insulators (QSHI). While the interplay of the $d$-wave superconductor and QSHI has been studied as a platform to realize Majorana corner modes (MCMs), we show that the addition of the spin texture enables the tunability of these MCMs. Each corner of this hybrid system can host one or two Majorana modes depending on the system parameters, in particular, exchange strength and pitch vector of the spin texture. To characterize the higher order bulk topology, we compute the quadrupolar winding number, which directly corresponds to the number of MCMs acquiring a value of one for four corner modes and two for eight corner modes. We investigate and show the close resemblance in the topological phase diagrams obtained from the low energy effective Hamiltonian that reveals an emergent in-plane Zeeman field and spin-orbit coupling induced by the spin texture, and the real space tight binding lattice model. The microscopic pairing mechanism responsible for the appearance of SOTSC phase is investigated via an effective bulk pairing analysis, while a low-energy edge theory captures the mechanism behind tunability of MCMs. Our result paves the way for realizing SOTC with multiple MCMs which can be tuned via system parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2505_05222
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Engineering second order topological superconductor hosting tunable Majorana corner modes in magnet/$d$-wave superconductor hybrid platform
Subhadarshini, Minakshi
Mishra, Archana
Saha, Arijit
Mesoscale and Nanoscale Physics
Superconductivity
We theoretically study the noncollinear magnetic texture effect on second-order topological superconductor (SOTSC) phase generated in unconventional $d$-wave superconductors and two-dimensional (2D) quantum spin Hall insulators (QSHI). While the interplay of the $d$-wave superconductor and QSHI has been studied as a platform to realize Majorana corner modes (MCMs), we show that the addition of the spin texture enables the tunability of these MCMs. Each corner of this hybrid system can host one or two Majorana modes depending on the system parameters, in particular, exchange strength and pitch vector of the spin texture. To characterize the higher order bulk topology, we compute the quadrupolar winding number, which directly corresponds to the number of MCMs acquiring a value of one for four corner modes and two for eight corner modes. We investigate and show the close resemblance in the topological phase diagrams obtained from the low energy effective Hamiltonian that reveals an emergent in-plane Zeeman field and spin-orbit coupling induced by the spin texture, and the real space tight binding lattice model. The microscopic pairing mechanism responsible for the appearance of SOTSC phase is investigated via an effective bulk pairing analysis, while a low-energy edge theory captures the mechanism behind tunability of MCMs. Our result paves the way for realizing SOTC with multiple MCMs which can be tuned via system parameters.
title Engineering second order topological superconductor hosting tunable Majorana corner modes in magnet/$d$-wave superconductor hybrid platform
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2505.05222