Polarity propagation in the InSb/α-Sn/InSb heterostructure

Films of InSb{111}A,B grown on α-Sn(111)/InSb{111}A,B by molecular beam epitaxy behave as if the polarity of their surfaces could receive that of the initial InSb substrates. InSb on α-Sn(111)/InSb(111)B alternates the surface polarity with α-Sn thickness. Below 5 bilayers (BL) α-Sn, the growing InSb exhibits the B type of surface composed of Sb and beyond 5 BL it changes toward the A type. This is due to Sb segregation from the initial InSb(111)B substrate to the α-Sn surface. On the other hand, InSb on α-Sn(111)/InSb(111)A always grows with the A-type surface via formation of the intermixing layers of (${\mathrm{In}}_{\mathit{x}}$ ${\mathrm{Sn}}_{1\mathrm{-}\mathit{x}}$)Sb, decreasing the value of x with increasing InSb thickness.