Magnetoelectric Mapping as Observed in Quantum Coherence Phenomena under Strong Spin-Orbit Interaction

A magnetoelectric mapping is demonstrated between dephasing effects of the magnetic vector potential and effects of an effective vector potential describing spin-orbit interaction. The experiments use spin-dependent mesoscopic quantum transport experiments on the narrow-gap semiconductor InSb and the semimetal Bi, both materials with strong spin-orbit interaction. The spin-orbit-induced antilocalization signature in transport allows determination of spin coherence lengths in narrow InSb and Bi wires. Spin coherence lengths are observed to increase with decreasing wire widths. The geometrical effect of width can be understood from the magnetoelectric duality between the Aharonov-Bohm phase and the Aharonov-Casher phase.