Computational design of 2D materials: Square-lattice monoatomic group IV elements

Square lattice structures have been theoretically predicted and experimentally observed in various two-dimensional (2D) systems and the common honeycomb lattices. Nevertheless, the stability of most square-structured materials remains unknown, especially group-IV materials. This study uses density functional theory to explore monoatomic group-IV materials' structural and electronic properties (C, Si, Ge, Sn) arranged in square and honeycomb lattices. According to the obtained band structures and projected density of states (PDOS), the electronic properties of this square structure are found to be metallic. Our calculations reveal a distinct energetic and dynamical preference for specific lattice configurations. In particular, the square-structured Sn is energetically more favorable than its honeycomb counterpart, stanene, suggesting an alternative stable configuration for this material. Phonon dispersion analysis further confirms that most studied group-IV materials exhibit sufficient dynamical stability, indicating their potential to exist under appropriate growth conditions. These findings advance the understanding of how lattice symmetry influences the structural and electronic behavior of 2D group-IV materials. By clarifying the stability of these materials, our study provides a foundation for further exploration of interfacial phenomena and the design of atomically thin layers with tunable properties. This expands the design space for next-generation nanoelectronic and surface-based devices, offering new insights into how surface symmetry and stability can be engineered at the atomic scale.