A band structure scenario for the giant spin-orbit splitting observed at the Bi/Si(111) interface

Understand

The Bi/Si(111) (sqrt{3} x sqrt{3})R30 trimer phase offers a prime example of a giant spin-orbit splitting of the electronic states at the interface with a semiconducting substrate.

• We have performed a detailed angle-resolved photoemission (ARPES) study to clarify the complex topology of the hybrid interface bands.
• The analysis of the ARPES data, guided by a model tight-binding calculation, reveals a previously unexplored mechanism at the origin of the giant spin-orbit splitting, which relies primarily on the underlying band structure.
• We anticipate that other similar interfaces characterized by trimer structures could also exhibit a large effect.