Critical exponents in percolation model of track regions with different depth distribution

Abstract

As a result of irradiation with Xe with E = 250 MeV in InP at room temperature [1] defects, similar to the "chain of pearls”, which are placed along the trajectory of the ions at depths ranging from 35 to 100 nm and from 7 to 10 microns have been identified. Such defects called tracks, and they can occur at different depths and have different shapes. Tracks were examined like a chain of deal spherical regions; it was assumed that each incident ion creates one such chain. In this model, we assume that the track is formed randomly, but in that place of the ion path, where the energy value, which loses each ion to the unity of the way, is above some threshold value. As a result of irradiation the number of tracks will continue to grow, areas of the single tracks modified substance continue to overlap, form of modificated matter becomes more complicated, creating branched structure. Percolation threshold, fraction of spanning cluster modified material for different doses and different distributions of track areas in depth were evaluated. Based on the scaling hypothesis large-scale curve were constructed, critical exponents for this percolation model were established. Calculated values of critical exponents were compared with the known values for the model of continuous percolation. Parameters of the percolation and critical exponents depend on the distribution of track areas in depth, which indicates the difference in the order parameters of the track structure obtained for different distributions in depth. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20810