Symmetry-driven screening of multifunctional 2D monolayers with valleytronic and piezoelectric properties: a high-throughput study.

Two-dimensional (2D) materials that combine valley-dependent electronic behaviour with piezoelectric functionality present exciting prospects for multifunctional nanoelectronics and energy-harvesting devices. In this study, we perform a high-throughput screening of the Computational 2D Materials Database (C2DB) to identify non-magnetic 2D semiconductors with minimal atomic complexity (2-3 atoms per unit cell) and high crystal symmetry (space groups P3m1 and P6̄m2), focusing specifically on materials with band extrema (VBM/CBM) at the K and K' valleys. A total of 48 monolayers is found to satisfy these criteria. For each candidate, the band structures with spin-orbit coupling (SOC), Berry curvature distributions, and piezoelectric coefficients are computed. The results reveal several monolayers exhibiting strong valley-contrasting properties alongside significant electromechanical responses. Therefore, our research offers a collection of valley-piezotronic materials with great promise for experimental implementation in next-generation devices.