A new interatomic potential for the ferroelectric and paraelectric phases of LiNbO₃

Abstract

This paper reports a new interatomic potential for lithium niobate, which has been fitted to the structure and properties of the stoichiometric ferroelectric phase of the material. The potential is based on a fully ionic description of the material, with the shell model being used for the oxygen ions and a three-body potential representing the interactions of the niobium ions with the neighbouring oxygen ions. The potential set has been tested on the paraelectric phase, whose structure it reproduced to within a few per cent. The calculation of lattice properties including elastic constants and dielectric constants, as well as powder x-ray diffraction patterns of both phases, are reported.

Growth, defect structure, and THz application of stoichiometric lithium niobate

“…[134][135][136][137][138] Major improvements could be achieved recently by another set of interatomic potentials 139 reproducing the properties of both the ferroelectric and paraelectric phases of LiNbO 3 and yielding a generally better level of agreement with experiment. The new set of pseudopotentials was based on the GULP code 140 and could be used to determine the formation energies of various intrinsic and extrinsic defects.…”

“…161 To clarify the controversial situation, new potentials were simultaneously determined for the structures of LiNbO 3 (ferroelectric phase), Li 2 O, and Nb 2 O 5 using the free energy minimization option of the GULP code. 139 Based on the new potentials, formation energies of intrinsic defects in LiNbO 3 , such as vacancies, cation interstitials at structural vacancies (i.e., in empty oxygen octahedra), Frenkel and Schottky defects, were determined. 162,163 Subsequently, three reactions were separately investigated, where the antisite niobium was compensated by lithium or niobium vacancies and the interstitial niobium by lithium vacancies…”

Computer Modelling of Hafnium Doping in Lithium Niobate

“…This approach has been applied to a wide range of inorganic materials, with specific applications to LiNbO 3 reported in references [7][8][9][10][11]. The method makes use of interatomic potentials to describe the interactions between ions in the solid, as described in the next Section 2.1.…”

Computer simulation of metal co-doping in lithium niobate

“…Previous papers have presented a new potential model for LiNbO 3 [8] and reported the doping of structure by rare earth ions [9] and a range of trivalent ions [10]. This paper reports a computational study of the double doping of LiNbO 3 by Fe and Cu, Ce and Cu, Ce and Mn, Fe and Rh, and Ru and Fe.…”