Effect of quantum reflection over the barrier on thermionic refrigeration

Abstract

We study the effect of quantum reflection over the barrier (ROB) in a thermionic cooling device. We find that the performance of refrigerators can be enhanced by the ROB effect if the bias voltage and the lattice thermal resistance of the semiconductor in the barrier region are both sufficiently high. Furthermore, the figure of merit ZT can be higher due to the ROB effect if the workfunction of the cathode is low and the lattice thermal resistance is high. The overall optimum ZT calculated with and without the ROB effect are 6.5 and 7.1, respectively. The origin of the ROB correction to ZT is that the quantum reflection becomes asymmetric for the carrier transport in opposite directions.

A novel electrochemical system with adiabatic pre-charging and pre-discharging processes for efficient refrigeration

“…3. [37] CP2-127 Peltier modules Experimental 0.79 22.69 0.0348 Thermoelectric refrigerator [37] CP2-127 Peltier modules Experimental 1.16 29.53 0.0393 Thermionic-thermoelectric refrigerator [38] Ideal materials Simulated 1.4* 9.667 0.145 Thermionic refrigerator [39] Single barrier structure with ROB Simulated 1.9* 10.00 0.190 Thermionic refrigerator [39] Single barrier structure without ROB Simulated 2.1* 10.00 0.210 Magnetic regenerator [40] Gd, Gd-based alloys, and their composites Experimental…”

Hallmark of quantum skipping in energy filtered lensless scanning electron microscopy

“…1 It has been observed, e.g., for electrons, [2][3][4][5][6] neutrons, 7 and atoms, 8,9 and also has practical applications, e.g., in devices involving electron emission and injection. 10,11 Here, we show that a special situation of scanning electron microscopy, where the electron source is only a few nanometers away from the target, [12][13][14][15] is unique in that quantum skipping (i.e., repeated quantum reflections) is the only mechanism that allows electrons produced at the primary, nanoscale site, 14 to reach the macroscopic environment. Our simulations show that the ejected electrons, skipping away from the primary site, accumulate in the elastic channel.…”