3 research outputs found
Fermi gas energetics in low-dimensional metals of spessial geometry
Changes in the metal properties, caused by periodic indents in the metal
surface, have been studied within the limit of quantum theory of free
electrons. It was shown that due to destructive interference of de Broglie
waves, some quantum states inside the low-dimensional metal become quantum
mechanically forbidden for free electrons. Wave vector density in k space,
reduce dramatically. At the same time, number of free electrons does not
change, as metal remains electrically neutral. Because of Pauli exclusion
principle some free electrons have to occupy quantum states with higher wave
numbers. Fermi vector and Fermi energy of low-dimensional metal increase and
consequently its work function decrease. In experiment, magnitude of the effect
is limited by the roughness of metal surface. Rough surface causes scattering
of the de Broglie waves and compromise their interference. Recent experiments
demonstrated reduction of work function in thin metal films, having periodic
indents in the surface. Experimental results are in good qualitative agreement
with the theory. This effect could exist in any quantum system comprising
fermions inside a potential energy box of special geometry.Comment: 15 pages, 4 figure
Thermotunnel refrigerator with vacuum/insulator tunnel barrier: A theoretical analysis
The authors use two insulator layers in thermotunnel refrigerator to modify
the shape of the tunneling barrier so that electrons with high kinetic energy
pass it with increased probability. Theoretical analysis show that the overall
tunneling current between the electrodes contains an increased number of high
kinetic energy electrons and a reduced number of low energy ones, leading to
high efficiency. The particular case of vacuum gap and solid insulator layer is
calculated using digital methods. Efficiency remains high in the wide range of
the emitter electric field. The cooling coefficient is found to be as high as
40%-50% in the wide range of the emitter electric field.Comment: 9 pages, 3 figure