Germanene on Ag (111)

The fundamental properties are dramatically changed through the significant Ge-substrate chemical bondings, zone-folding effects, enhanced bucklings, and stacking configurations. The sufficient substrate Ag-layers in the calculations are utilized to simulate the stable geometric structures. The spin-dependent single- and many-particle interactions behave similarly. The various interlayer distances of the neighboring layers are comparable with one another. The theoretical predictions, which are conducted on the optimal geometries of Ge-adlayer and bilayer germanene on Ag (111) with the 3 × 3 and 4 × 4 super lattices, could be examined through experimental measurements. There exist certain important differences between the bilayer and monolayer germanene on Ag (111) in terms of the interlayer chemical bondings and the spin-dependent magnetic properties. It is almost impossible to delicately evaluate the 2D conduction electron density from the direction-dependent Fermi momenta in the presence/absence of spin splitting. The spin configuration in bilayer germanene/Ag (111), which presents a rather non-uniform spin-up and spin-down arrangement within an enlarged unit cell, mainly originates from the second-layer six Ge atoms. The (4px, 4py, 4pz) orbitals of Ge-atoms make the most important contributions to the ferromagnetic properties associated with the spin-created many-particle interactions.