Image Number 7 for United States Patent #8415761.
Exemplary embodiments of the invention include a thermoelectric material having an aligned polarization field along a central axis of the material. Along the axis are a first atomic plane and a second atomic plane of substantially similar area. The planes define a first volume and form a single anisotropic crystal. The first volume has a first outer surface and a second outer surface opposite the first outer surface, with the outer surfaces defining the central axis passing through a bulk. The bulk polarization field is formed from a first electrical sheet charge and a second opposing electrical sheet charge, one on each atomic plane. The opposing sheet charges define a bulk polarization field aligned with the central axis, and the bulk polarization field causes asymmetric thermal and electrical conductivity through the first volume along the central axis.