Coexistence of nontrivial topological properties and strong ferromagnetic fluctuations in quasi-one-dimensional A2Cr3As3
Abstract
Superconductivity in crystals without inversion symmetry has received extensive attention due to its unconventional pairing and possible nontrivial topological properties. Using first-principles calculations, we systemically study the electronic structure of noncentrosymmetric superconductors A2Cr3As3 (A = Na, K, Rb, and Cs). Topologically protected triply degenerate points connected by one-dimensional arcs appear along the C3 axis, coexisting with strong ferromagnetic (FM) fluctuations in the non-superconducting state. Within random phase approximation, our calculations show that strong enhancements of spin fluctuations are present in K2Cr3As3 and Rb2Cr3As3 and are substantially reduced in Na2Cr3As3 and Cs2Cr3As3. Symmetry analysis of pairing gap Δ(k) and spin-orbit coupling gk suggest that the arc surface states may also exist in the superconducting state, giving rise to possible nontrivial topological properties.
- Publication:
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npj Computational Mathematics
- Pub Date:
- April 2020
- DOI:
- 10.1038/s41524-020-0294-9
- arXiv:
- arXiv:1909.04346
- Bibcode:
- 2020npjCM...6...30X
- Keywords:
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- Condensed Matter - Superconductivity
- E-Print:
- We have some typos corrected and add discussion about the effect of ferromagnetic fluctuations on the band topology. We also add discussion on the topological property in the superconducting state with the symmetry indicators method recently proposed