Tomographic layer-by-layer analysis of epitaxial iron-silicide nanostructures by DFT-assisted STS

Origin of Magnetism in γ-FeSi2/Si(111) Nanostructures

“…As expected, the DOS for the fixed middle layers manifests a similar DOS as the bulk shows. Looking into the DOS of first-layer Fe atoms more closely, we can find a sharp peak centered around −0.8 eV, which is in good agreement with the experimental measurements using in-situ scanning tunneling microscopy [ 17 ]. This sharp peak mainly originates from the Fe layer that is closest to the free surface.…”

“…The DOS spectra profiles of Fe atoms for Si-terminated and Fe-terminated interfaces are shown in Figure 3 a,b, respectively. The Fe atoms at the free surface (A and A’) exhibit similar DOS as in the free-standing nanoslab without Si substrate ( Figure 2 b), all of which show the characteristic sharp peak centered around −0.8 eV that matches the experimental measurement [ 17 ]. On the contrary, the interface Fe atoms (B and B’) manifest different DOS features for both types.…”

“…( b ) DOS of Fe atoms in the first two Fe layers (A and B) near the surface and the corresponding calculated spin moments. The red curve is an experimental DOS reproduced from [ 17 ].…”

“… Atomic structures and DOS of Fe atoms in γ-FeSi 2 /Si(111) epitaxial nanoslabs with two types of interface: ( a ) Si-terminated and ( b ) Fe-terminated. The red curve is an experimental DOS reproduced from [ 17 ]. …”

“…In transition-metal silicide nanostructures, even Si-rich silicides can exhibit ferromagnetic ordering. For example, a ferromagnetic response has been observed for iron disilicide FeSi 2 nanostructures, and such magnetic properties are not found in other transition metal silicides like NiSi 2 or CoSi 2 [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Multiple phases were reported for FeSi 2 nanostructures, such as , , , and .…”