  We show that for a quantum wire with a local asymmetric scattering potential
the principal channels for charge and heat rectification decouple and
renormalise differently under electron interactions, with heat rectification
generally being more relevant. The polarisation of the rectification results
from quantum interference and is tuneable through external gating. Furthermore,
for spin polarised or helical electrons and sufficiently strong interactions a
regime can be obtained in which heat transport is strongly rectified but charge
rectification is very weak.
