Consideration of linear topological defects in silicene through molecular dynamics and ab-initio calculations

Abstract

Defects in two-dimensional materials are of significant interest because they have a significant impact on the properties of the material. Using the molecular dynamics method and ab-initio calculations, linear topological defects in silicene are studied. Silicene has an extended honeycomb structure, a two-dimensional hexagonal structure with two atoms per unit cell, one above and one below relative to the plane of the sheet. Silicene can have two energetically equivalent structures, depending on which of the two atoms of the unit cell is located above. Topological defects are formed at the junction of these structures. Such defects do not imply the need to break bonds and cannot disappear from the structure otherwise than through the annihilation of such topological defects of different signs. Relaxed structures of linear topological defects in silicene are shown, defect energies are calculated, and molecular dynamics and ab-initio data are compared. Similar defects exist in other two-dimensional materials of group IVA, such as germanene, stanene, plumben, etc. As a result of the work using ab-initio, the existence of this type of defects was confirmed and options for its experimental detection were suggested.