  We show that coherent electron transport through zero-dimensional systems can
be used to tailor the shape of the system's transmission function. This
quantum-engineering approach can be used to enhance the performance of quantum
dots or molecules in thermal-to-electric power conversion. Specifically, we
show that electron interference in a two-level system can substantially improve
the maximum thermoelectric power and the efficiency at maximum power by
suppressing parasitic charge flow near the Fermi energy, and by reducing
electronic heat conduction. We discuss possible realizations of this approach
in molecular junctions or quantum dots.
