Rashba diamond in an Aharonov-Casher ring

Spin interference due to Rashba spin-orbit interaction (SOI) in a ballistic two-dimensional electron gas (2DEG) ring conductor submitted to a bias voltage is investigated theoretically. We calculate the scattering matrices and differential conductance with lead-ring junction coupling as an adjustable parameter. Due to the interference of electronic waves traversing the ring, the differential conductance modulated by both bias voltage and SOI exhibits a diamond-shaped pattern, thus termed as \ti{Rashba diamond}. This feature offers a supplementary degree of freedom to manipulate phase interference.