Figure 1.

Illustration of CISS (ideal case). The directional electron transmission is spin-selective, and the unfavored spin is flipped and reflected. The chiral component is indicated by the blue helix and is assumed to favor the transmission of electrons with spin parallel to momentum. The electrons on both sides (L and R) of the chiral component are labeled with their spin-specific (→ or ←) electrochemical potentials μ_L(R)→(←). At thermodynamic equilibrium, any net charge or spin current in and out of electrodes is forbidden, but when biased, the chiral structure supports a charge current I and collinear spin currents on both sides I_sL and I_sR. The positive currents are defined as right-to-left, i.e. when the (spin-polarized) electrons flow from left to right.