Promoting spin-polarized states in Bi/Si(111) interface mediated by Ba intercalation for advanced spintronics applications

Manipulation of electronic properties through modification of interface has become a successful strategy to adjust 2D materials for applications in advanced electronic and spintronic devices. Here, we demonstrate an effective approach to enrich the electronic properties of the Bi/Si interface, known to be a Rashba semiconductor, through Ba intercalation, leading to the emergence of spin-split states with advanced spin texture at the Fermi level, which opens a great potential of Ba-Bi monolayer on Si(111) as an advanced spintronics material. Using various experimental techniques and accurate DFT calculations, we find that adsorption of submonolayer of Ba onto the mixed alpha/beta-Bi/Si(111)-root 3 x root 3 surface leads to formation of the ordered Ba-Bi epitaxial layer of root 7 x root 7 periodicity demonstrating unique spin-polarized states in its band structure, which makes the system suitable for realizing a tunable spin current regime.