Materials search algorithms for square net Dirac materials

Square net materials can exhibit Dirac nodal lines, as exemplified by ZrSiS, whose striking linear dispersion spans 2eV. Since the discovery of ZrSiS, there has been a search to find more square net Dirac materials. To this end, we derived a symmetry classification of square nets, which reveals that the glide symmetry in ZrSiS is not necessary to protect a Dirac crossing. We use our classification to derive a materials search algorithm, predicting new square net materials in both symmorphic and non-symmorphic space groups. We further derive a geometric tolerance factor to refine the materials search. Finally we discuss correlated square net materials.