Simulation of atomic distribution of guest atoms in layered 1T-TiS2 crystal using Monte Carlo method and its effect on the magnetic properties and local structures

Monte Carlo simulations of atomic distribution of intercalated guest atoms in the layered 1T-TiS2 have been performed by taking into account attractive or repulsive pair-interactions between the neighboring guest atoms in the a-axis plane and along the c-axis of the crystal lattice (lattice size for computation: 18 x 18 x 6). X-ray diffraction patterns are calculated from the atomic distributions obtained using four kinds of pair-interactions, in qualitative agreement with the experimental data of the 2a x 2a x 2c short-range ordered structure for x = 0.15, and superlattices of 2 root 3a x 2a x 2c for x = 0.25 and root 3a x root 3a x 2c for x = 0.333 with fractional site occupancy in FexTiS2. From the calculated atomic distributions, we have evaluated the number of neighboring guest atoms, the formation of clusters, and percolation cluster, as well as its dimension, all of which are responsible for the dynamical relaxation behaviors of the thermoremanent magnetization observed in the spin- and cluster-glass phases of FexTiS2. Using the present results and EXAFS data, we have further discussed on the change in the local structures near the host sulfur atoms by intercalation of the guest atoms in MxTiS2.