Unusual In-Plane Field Dependence of Spin Resolved Magnetic Focussing in 2D Hole Systems

The need for an all-electrical method of spin control has driven great interest in the spin-orbit interaction. Transverse magnetic focussing provides a method to study spin dynamics by creating spatial separation of spin. We perform magnetic focussing of holes in high symmetry (100) GaAs/AlGaAs heterostructures. We compare focussing in single heterojunction (very strong Rashba) and quantum well (weaker Rashba) structures. While the period of the focussing peaks is the same, we discuss several features that differentiate the spin resolved peaks in these systems. By varying the focussing length we extract the focussing decay length for each spin peak. We also study the dependence of the spin peak separation on the 2D density. Finally, we observe unusual behaviour of the height of the spin peaks with in-plane magnetic fields.