Dissipation in quantum tunnel junctions

Based on experimental data, we propose a model to evaluate the energy dissipated during quantum tunneling processes in solid-state junctions. This model incorporates a nonlinear friction force expressed in the general form f (x) = gamma v(x)(alpha), where gamma is the frictional coefficient, which is fitted to data. We study this by applying voltages just below the barrier height up to near breakdown voltages. Furthermore, by lowering the temperature and adjusting the applied voltage to the junction, the effect on dissipation caused by the variation in barrier height is examined. We underline that the crucial dependency of dissipation on the fraction of particle energy lost is modulated by two primary mechanisms: the application of voltage and the variation of temperature. The fraction of energy dissipated decreases, in general, for increasing energies of the tunneling particles at a given temperature. However, for a given energy of the tunneling particle, the present work demonstrates a turning point at a temperature of 137 K, after which the dissipated energy starts increasing for higher temperatures. The latter can possibly be due to the increase of electron-phonon interactions, which become predominant over barrier height reduction at higher temperatures, and hence, we identify T = 137 K as a critical temperature for a change in the dissipative characteristics of the solid-state junction under consideration. Notably, the study also identifies significant changes in dissipation parameters, gamma and alpha, above 137 K, exhibiting a linear decline and underscoring the importance of further research at higher temperatures. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).