A new topological semimetal candidate: SmMnBi2

• Published in: Acta crystallographica Section B, Structural science, crystal engineering and materials Structural science, crystal engineering and materials, 2021-08, Vol.77 (4), p.577-583
• Main Authors: Krishnan, Sudha, Besara, Tiglet
• Format: Article
• Language: English
• Subjects: Antimony; Bismuth; Dirac or Weyl semimetals; Rare earth elements; single crystal growth; Slabs; SmMnBi2; Stacking; topological materials; Topology
• ISSN: 2052-5206; 2052-5192; 2052-5206
• DOI: 10.1107/S2052520621005849

The new compound SmMnBi2 has been synthesized by the self‐flux method and shown to crystallize in space group I4/mmm with a = 4.5054 (4) Å, c = 20.5914 (19) Å and Z = 4. Its structure comprises two‐dimensional square Mn‐nets layers, puckered rock‐salt‐like SmBi slabs and two‐dimensional square Bi‐nets layers, alternating along the c axis in an …Mn‐net–SmBi slab–Bi‐net–SmBi slab–Mn‐net… sequence. Surprisingly, the atomic arrangement differs from its neighboring compound EuMnBi2 which has similar layers but with a different stacking arrangement. This gives rise to edge‐shared square planar MnBi4 polyhedral layers in SmMnBi2 while EuMnBi2 has edge‐shared MnBi4 tetrahedral layers. The MMnX2 (M = alkaline earth/rare earth metals, X = Sb/Bi) family has emerged as topological Dirac or Weyl semimetal candidates, all of them sharing similar structural features. Although SmMnBi2 has a different stacking arrangement to EuMnBi2, its layer structure still makes it a topological Dirac or Weyl semimetal candidate. The crystal structure of SmMnBi2, a new topological semimetal candidate, is investigated and compared to the structures of existing topological semimetals.