Topological d+s wave superconductors in a multi-orbital quadratic band touching system
| Autor: | Sim, GiBaik, Mishra, Archana, Park, Moon Jip, Kim, Yong Baek, Cho, Gil Young, Lee, SungBin |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 100, 064509 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.100.064509 |
| Popis: | Realization of topological superconductors is one of the most important goals in studies of topological phases in quantum materials. In this work, we theoretically propose a novel way to attain topological superconductors with non-trivial Fermi surfaces of Bogoliubov quasiparticles. Considering the interacting Luttinger model with $j\!=\!3/2$ electrons, we investigate the dominant superconducting channels for a multi-orbital quadratic band-touching system with finite chemical potential, which breaks the particle-hole symmetry in the normal state. Notably, while the system generally favors d-wave pairing, the absence of the particle-hole symmetry necessarily induces parasitic s-wave pairing. Based on the Landau theory with $SO(3)$ symmetry, we demonstrate that two kinds of topological superconductors are energetically favored; uniaxial nematic phase with parasitic $s$ wave pairing ($d_{(3z^2-r^2)}\!+\!s$) and time-reversal-symmetry broken phase with parasitic $s$ wave pairing ($d_{(3z^2-r^2,xy)}\!+\!id_{x^2-y^2}\!+\!s$). These superconductors contain either nodal lines or Fermi pockets of gapless Bogoliubov quasiparticles and moreover exhibit topological winding numbers $\pm2$, leading to non-trivial surface states such as drumhead-like surface states or Fermi arcs. We discuss applications of our theory to relevant families of materials, especially half-heusler compound YPtBi, and suggest possible future experiments. Comment: 14 pages, 8 figures |
| Databáze: | arXiv |
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