The geometric structure of the surface of silicon nanotube determines its unique
properties. The new dual nature of the surface structure of a silicon nanotube depending on the tube type
was revealed by ab-initio modeling using the density functional theory. The rippled structure of the surface
turned out to be the most energetically favorable form for the (n, n) type of the tube, and the smooth shape
of the nanotube walls was the main stable form for the nanotubes of the (n, 0) type. The dual nature of the
surface structure of silicon nanotubes is explained by the dependence of the formation of -bonds on the
tube surface on the mutual position of unhybridized p-orbitals of silicon atoms