Atomistic simulation of trivalent ions doped in the hexagonal LuMnO3 ferroelectric phase

The interatomic potentials for multiferroic hexagonal LuMnO3 (h-LMO) in its ferroelectric (FE) phase was obtained for empirical fitting procedure and applied to study the effects of a series of trivalent metal and rare-earth dopants on its structural and ferroelectric distortions. The potential parameters found accurately reproduce lattice parameters (error below 0.3%), interatomic distances, pressure effect on the lattice parameters, and tilting angles of the MnO5 polyhedron. We investigated doping at Mn, Lu1 and Lu2 atom sites. It was found that the doped Mn atom site is the most energetically advantageous site for both the metal (Al, Ga, Fe and Cr) and rare-earth (La, Nb, Sm, Eu, Gd, Ho, Er, Yb, Y and Sc) atoms studied. The M-O3/O4 distances decrease when the Mn3+ ion site is doped by trivalent metal ions. The effects on the FE distortion of the material under doping and changes in the tilting angle of the M/MnO5 polyhedron were analyzed.