Influence of the wideband matrix promote phonon modes on tunnel cvc of semiconductor quantum dots

Background. Study of the problem of controllability of quantum effects, associated with the dissipative tunneling dynamics in low-dimensional systems of different nature, is an actual problem of modern condensed matter physics. The research of driven tunneling effects in systems of semiconductor quantum dots, as well as in experiments with a scanning tunneling / atomic force microscope in the study of the low-dimensional structures parameters, has been intensified in recent years. The objectives of this work are the following: experimental study of tunnel current-voltage characteristics, obtained under visualization of the local density of states in quantum dots InAs / GaAs (001) with usage of the tunneling atomic force microscopy; theoretical study of the dissipative regime for 1D-tunneling with the influence of individual local phonon modes for a wide-matrix in an external electric field at finite temperature. Materials and methods. The authors used the method of scanning tunneling microscopy in ultrahigh vacuum for measuring spatial and energy distribution for the local density of states in the InAs quantum dots. The test samples were grown on the substrate $n^+$-GaAs ( 001) of AGChO -mark, doped by Sn, with usage of the hydride epitaxy method for organic metal compounds at atmospheric pressure. The instanton method in approximation of the rarefied gas for instanton - anti-instanton pairs was used for calculation of the 1D-dissipative tunneling probability in a model of a double- well oscillator potential up to the pre-exponential factor. Results. The tunneling current-voltage characteristic with several randomly spaced peaks were obtained in the experiment on visualization of the local density of states in quantum dots InAs / GaAs (001) with usage of the tunneling atomic force microscopy in ultrahigh vacuum. The authors suggest a model of 1D-dissipative tunneling to interpret the experimentally found features of the tunneling current-voltage characteristics for the contact of the atomic force microscope probe to the surface of a quantum dot. It was found, that the influence of the promote modes for the wide-band matrix on the probability of 1D-dissipative tunneling leads to the appearance of two distinct peaks (stable and unstable ones) in the corresponding field dependence. Conclusions. It is shown that the theoretical dependence of the 1D - dissipative tunneling probability with account of the promoting mode influence of a wide-band matrix on the external electric field only partially agrees with the experimental current-voltage characteristic of the contact of the atomic force microscope probe to the surface of the quantum dot InAs / GaAs (001). Instead of a series of nonequidistant peaks the theoretical model gives only two, one of which is unstaible. For better concordance of the theoretical model and the experimental data it may be more appropriate to account of the influence of two local modes for wide-band matrix. It is shown that in addition to the resonant tunneling regime, as suggested earlier, it is also necessary to consider the contribution of the dissipative tunnel regime (in the limit of “weak” damping), which may appear in the tunneling current-voltage characteristics for semiconductor quantum dots, placed in a wide-band matrix.