Topological superconductivity and large spin Hall effect in the kagome family Ti6X4 (X = Bi, Sb, Pb, Tl, In)

Abstract

Topological superconductors (TSC) become a focus of research due to the accompanying Majorana fermions. However, the experimentally reported TSC are extremely rare. The recent experiments reported the kagome TSC AV${}_3$Sb${}_5$ (A=K, Rb, Cs), which exhibit unique superconductivity, topological surface states (TSS), and Majorana bound states. More recently, the first titanium-based kagome superconductor CsTi${}_3$Bi${}_5$ with nontrivial topology was successfully synthesized as a perspective TSC. Given that Cs contributes little to the electronic structures of CsTi${}_3$Bi${}_5$ and binary compounds may be easier to be synthesized, here, by density functional theory calculations, we predict five stable non-magnetic kagome compounds Ti${}_6$X${}_4$ (X = Bi, Sb, Pb, Tl, In) which exhibit superconductivity with critical temperature Tc = 3.8$-$5.1 K, nontrivial $\mathbb{Z}$${}_2$ band topology, and TSS close to the Fermi level. In addition, the large intrinsic spin Hall effect is obtained in Ti${}_6$X${}_4$, which is caused by gapped Dirac nodes and nodal lines due to a strong spin-orbit coupling. This work offers new platforms for TSC and spintronic devices.

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Cited by in corpus (5)

• Large kagome family candidates with topological superconductivity and charge density waves
• Superconducting, topological and transport properties of kagome metals CsTi${}_3$Bi${}_5$ and RbTi${}_3$Bi${}_5$
• Tuning the Intrinsic Spin Hall Effect by Charge Density Wave Order in Topological Kagome Metals
• Truly local topological dynamics of driven defects in Chern insulator
• Double-layer Kagome Metals Pt3Tl2 and Pt3In2