  Reservoir engineering is a powerful tool for the robust generation of quantum
states or transport properties. Using both a weak-coupling quantum master
equation and the exact solution, we show that directional transport of
electrons through a double quantum dot can be achieved through an appropriately
designed electronic environment. Directionality is attained through the
interference of coherent and dissipative coupling. The relative phase is tuned
with an external magnetic field, such that directionality can be reversed, as
well as turned on and off dynamically. Our work introduces fermionic reservoir
engineering, paving the way to a new class of nanoelectronic devices.
