Emergent dual topology in the three-dimensional Kane-Mele Pt 2 HgSe 3

Jacutingaite (Pt2HgSe3) is a naturally-occurring layered mineral that, when exfoliated into monolayers, could provide the first physical realization of the Kane-Mele model for a quantum spin Hall insulator. In its bulk form, jacutingaite has been predicted to combine weak and crystalline topological phases. This paper shows that such dual topology emerges from a crucial and surprisingly strong interlayer coupling.