Half-integer channel plateaus from a symmetric bias window ($G_d=(e^2/h){\sum }_n[T_n({\mu }_S)+T_n({\mu }_D)]$)

For rigid spin-degenerate channel transmissions and ${\mu }_{S,D}=E_F\pm eV/2$, differentiating $I=(2e/h){\sum }_n{\int }_{{\mu }_D}^{{\mu }_S}{T}_n(E)dE$ gives $G_d=(e^2/h){\sum }_n[T_n({\mu }_S)+T_n({\mu }_D)]$. If the two edges sample neighboring integer channel counts, $G_d$ is a half-integer multiple of $2e^2/h$. Explicit bias dependence of the potential adds terms; the apparent fraction does not imply fractional carriers.