Table 1 Topological crystalline (TC) insulating materials for SGs87,140, and 221.

These SGs all own the same strong SI factor group, ℤ8, but with different other weak SI factor groups. The numbers in the parenthesis following the name of material are the nonvanishing SI in the corresponding XBS. The SI is obtained by qiCi mod Ci, where ai has a common factor larger than 1, which corresponds to the subscript of the factor groups of XBS. The blue color denotes the materials carefully discussed in this work.

SGXBSMaterial (SI)
872 × ℤ8Au4Ti (10), Hf5Te4 (11)
1402 × ℤ8Pt3Ge (04), SiTa2 (11)
2214 × ℤ8AlX (X = Sc, Y) (03)
XB6 (X = Ca, Sr, Ba) (03)
BeTi (03), CaPd (20), CsPbBr3 (23)
CsGeBr3 (23), CsSnI3 (23)
Ca3PbO (22), XPt3 (X = Pb, Sn) (34)