Temperature-Induced Revolving Effect of Electronic Flow in Asymmetric Double-Barrier Semiconductor Heterostructures

We theoretically report a remarkable revolving effect of electron flow when applying a lattice temperature gradient across an asymmetric double-barrier heterostructure. Depending on whether the lattice temperature increases or decreases, we demonstrate that electrons respectively absorb or emit a phonon and subsequently go back to the reservoir from which they have been injected. Our simulation code, which self-consistently solves the nonequilibrium Green's function framework and the heat equation, is capable of calculating the electron temperature and electrochemical potential inside the device. By investigating those nonequilibrium thermodynamic quantities, we show that the revolving effect is due to the sign inversion of the local electron distribution. In particular, simulation results evidenced a variation of the electrochemical potential inside the device to compensate the temperature gradient, and to maintain the electrostatic neutrality in the access regions. Finally, we propose an analytic model which provides an intuitive picture of the effect, and discuss the possibility to use such behavior in the new context of heat management in nanostructures.