Cataloging High-Quality Two-Dimensional van der Waals Materials with Flat Bands

Benefited from the lower dimensionality compared to their 3D counterpart, 2D flat-band systems provide cleaner lattice models, easier experimental verification, and higher tunability, which make the 2D van der Waals (vdW) system an ideal playground for exploring flat-band physics as well as their potential applications. Given the vast amount of research in the field of flat bands, a simple and efficient approach to search for realistic vdW materials with flat bands is still missing. Here, a two-tier framework to filter and diagnose high-quality flat-band vdW materials by combining high-throughput first-principles calculations and the proposed 2D flat-band score criterion is presented. Based on systematic geometrical analysis, 861 potential monolayer vdW materials are initially obtained amounting to 187,093 structures as stored in the Inorganic Crystal Structure Database. By applying the 2D flat-band score criterion, 229 flat-band candidates are efficiently identified, among which a sub-catalog of 74 materials with flat bands right next to the Fermi level is further provided to facilitate experimental verification. All these efforts to screen experimentally available flat-band candidates will certainly motivate continuing exploration toward the realization of this class of special materials and their applications in material science.