Eur. Phys. J. B 15, 469-474 (2000)
https://doi.org/10.1007/s100510051148

Percolation with constraints in the highly polarizable oxide KTaO₃:Li

¹ Physics department, Rostov State University, 5 Zorge Str., 344090 Rostov-on-Don, Russia
² A.F. Ioffe Physical-Technical Institute, 194021 St. Petersburg, Russia
³ Fachbereich Physik, University of Osnabrueck, 49069 Osnabrueck, Germany

Received: 26 August 1999
Revised: 27 December 1999
Published online: 15 June 2000

Abstract

Experimental data on the temperature and electric field dependence of the Second Harmonic Generation Intensity in the solid solution KTaO₃:Li is analyzed in the framework of a new percolation-type approach which considers the history of cluster formation averaged over a large number of samples. In order to take into account that two cluster dipole moments turn when joining clusters together, a constraint is imposed on the cluster growth. This constraint leads to cluster-size saturation just after the percolation threshold. Owing to this circumstance, the connected cluster coexists with free clusters in some range of the impurity concentration and temperature. There is qualitative agreement between the computational results and experiments on Second Harmonic Generation intensities. The algorithm was written in C++ which allowed realistic computations to be performed on a standard PC.