Homogenized spin–charge transport in random heterogeneous chiral molecular media

We formulate an effective-medium theory for scale-separated bulk diffusive or hopping spin-charge transport in random heterogeneous chiral media. Starting from a supplied steady, local, open-system linear-response law for a four-component charge-spin voltage field, periodic or stationary-ergodic cell problems give deterministic homogenized coefficients while preserving positivity and Onsager-Casimir reciprocity. The effective charge-spin blocks describe convention-qualified bulk conversion after disorder, tortuosity, current focusing, and orientational averaging; terminal lead fluxes, absorbed angular momentum, spin accumulation, and detector voltages additionally require specified boundary conditions. For a rank-one longitudinal path ansatz, the weak-contrast coefficient along film normal n is proportional to OCISS(n)=χ(p⋅n)3. Random positions can therefore support longitudinal conversion, whereas isotropic orientations and head-tail-symmetric nematic order cancel this rank-one contribution even in an enantiopure medium. A one-dimensional bulk-film solution gives the internal spin-charge fields and terminal fluxes for specified contacts. Spin accumulation is odd under reversal of the reciprocal chirality-induced spin selectivity coefficient, whereas the passive scalar two-terminal conductance correction is even for the nonmagnetic spin-diagonal boundary problem considered here.