First-Principles Simulation of Structural and Magnetic Properties of H-Terminated Silicene and Germanene

Density-functional-theory calculations have been performed to investigate the magnetism induced in silicene and germanene by hydrogen terminations. We varied the H-terminated structures from monomers to pentamers. Silicene and germanene exhibit magnetic properties after H termination, as indicated by the appearance of magnetic moments. The greater the magnetic moment, the more H atoms are added in the same direction. Conversely, H atoms added in the opposite direction reduce the magnetic moment. We calculated the adsorption energy for each variation of H-terminated silicene and germanene. The results show that both have negative adsorption energies. H-terminated silicene has a more negative adsorption energy than H-terminated germanene. For example, pentamer silicene has an adsorption energy of -10.37 eV, while pentamer germanene has an adsorption energy of -7.39 eV. This indicates that H is more easily adsorbed on silicene. Thus, H-terminated silicene and germanene are suitable for magnetic material device applications.