Asymmetric band gaps in a Rashba film system

The joint effect of exchange and Rashba spin-orbit interactions is examined on the surface and quantum well states of ${\mathrm{Ag}}_{2}\mathrm{Bi}$-terminated Ag films grown on ferromagnetic Fe(110). The system displays a particular combination of time-reversal and translational symmetry breaking that strongly influences its electronic structure. Angle-resolved photoemission reveals asymmetric band-gap openings, due to spin-selective hybridization between Rashba-split surface states and exchange-split quantum well states. This results in an unequal number of states along positive and negative reciprocal space directions. We suggest that the peculiar asymmetry of the discovered electronic structure can have significant influence on spin-polarized transport properties.