About resonance tunneling of quasiparticles through nanocontact «aluminum – aluminium oxide – aluminum» at low temperatures

Abstract

Within the framework of the density functional theory using the method of non-equilibrium Green's function in the local density approximation investigated quantum transport properties nanoscale contact «aluminum – aluminum oxide – aluminum» (Al – Al₂O₃ – Al). Computer modeling of quantum transport characteristics is implemented in the program Atomistix ToolKit with Virtual NanoLab. Calculated current-voltage, dI/dV-characteristics, transmission spectrum and the spectral current reporting nanocontact. On the basis of computer simulation, it is shown that as the magnitude of the bias voltage increases, the maximum of the transmission function shifts from the positive energy side to the negative one. From the shape of the transmission spectrum of a nanocontact, it can be assumed that the main mechanism of electron transport in such structures is the resonance tunneling of quasiparticles. In the current-voltage characteristic features of nanostructures observed at voltages of ± 0,54 V, 0,2 V, 0,08 V due to the resonant tunneling of quasiparticles. The current-voltage characteristic has a significant portion of the negative differential resistance. Features of electronic transport, observed on the current-voltage characteristic, also appear on the dI/dV-characteristic of the nanocontact. It is found that the differential conductivity has two main peaks with a value of ~ 26 nS at a bias voltage of ± 0,45 V inherent in tunnel junctions. It is established that the spectral current increases with a sharp decrease in the value of the differential conductivity, and vice versa, decreases with a sharp increase in its value, and its maximum value is manifested at a bias voltage of 0,45 V. The obtained results of a model study of a nanocontact «Al – Al₂O₃ – Al» can be useful for the calculation of new advanced electronic devices of cryogenic nanoelectronics.