A percolation model is proposed to explain the structural phase transitions
found in Li1−xHxIO3 mixed crystals as a function of the
concentration parameter x. The percolation thresholds are obtained from Monte
Carlo simulations on the specific lattices occupied by lithium atoms and
hydrogen bonds. The theoretical results strongly suggest that percolating
lithium vacancies and hydrogen bonds are indeed responsible for the solid
solution observed in the experimental range 0.22<x<0.36.Comment: 4 pages, 2 figure