This paper explores the connection between the spin Hall effect and higher-order topological insulators (HOTIs). Using a combination of ab initio calculations and tight-binding modeling, the authors demonstrate that a non-zero bulk midgap spin Hall conductivity (SHC) emerges within the HOTI phase. This connection is then used as a criterion in high-throughput density functional theory calculations to identify seven stable two-dimensional HOTIs: BiSe, PbF, PbBr, PbCl, HgTe, and BiTe in both GaSe and CH prototype structures. The findings are validated through real-space projections of midgap states and topological invariant calculations.

Marcio Costa, Gabriel R. Schleder, Carlos Mera Acosta, Antonio C. M. Padilha, Frank Cerasoli, Marco Buongiorno Nardelli, Adalberto Fazzio