  Exploiting inversion symmetry breaking (ISB) in systems with strong
spin-orbit coupling promises control of spin through electric fields - crucial
to achieve miniaturization in spintronic devices. Delivering on this promise
requires a two-dimensional electron gas with a spin precession length shorter
than the spin coherence length and a large spin splitting so that spin
manipulation can be achieved over length scales of nanometers. Recently, the
transition metal oxide terminations of delafossite oxides were found to exhibit
a large Rashba spin splitting dominated by ISB. In this limit, the Fermi
surface exhibits the same spin texture as for weak ISB, but the orbital texture
is completely different, raising questions about the effect on quasiparticle
scattering. We demonstrate that the spin-orbital selection rules relevant for
conventional Rashba system are obeyed as true spin selection rules in this
correlated electron liquid and determine its spin coherence length from
quasiparticle interference imaging.
