Figure 1

(a) The electric field is perpendicular to the ferromagnet surface while the order parameter direction , is defined by the angle θ relative to . Whatever the direction of k, the Rashba magnetic field B_R of direction k × E lies in the plane. (b) The Rashba split bands of a non-magnetic metal. The two Fermi sheets emerge from a “Dirac point” near the bottom of the illustration. For the magnetic case the two Fermi sheets are disconnected. (c) For a perpendicular the electron spins make a constant angle δ to the vertical such that the projection is as in (b). The additional exchange splitting increases as E². (d) Same but for parallel to the plane. With along the y-direction the majority and minority Fermi seas shift along the x-axis in opposite directions. The tilt of the spin relative to is no longer a constant being zero along the x-axis and a maximum along the y-axis.