Behavior of the local mode potential in BaTiO3 studied by Effective Hamiltonian numerical simulations

TL;DR

This study uses effective Hamiltonian simulations to analyze how the local potential energy landscape in BaTiO3 evolves, revealing the transition from off-centered minima in ferroelectric phases to a centered minimum in the paraelectric phase.

Contribution

It provides a detailed numerical analysis of the local mode potential energy behavior in BaTiO3, highlighting the evolution of the Ti ion's potential minima across phases.

Findings

The Ti ion's potential minimum shifts from off-centered in ferroelectric phases to centered in the paraelectric phase.

The soft mode behavior arises from the average response of the Ti ion to potential changes.

The time-averaged potential minimum is centered at the paraelectric phase and off-centered at the ferroelectric phase.

Abstract

The behavior of the local mode potential energy in the unit cell of BaTiO3 is studied by effective Hamiltonian numerical simulations. The study is focused on the evolution of the potential minimum felt by the Ti ion. At the paraelectric phase, the single instantaneous minimum is located at one of eight off-centered regions at the body diagonals of the unit cell. The study shows graphically how the soft mode behavior of the perovskite comes from the average response of the Ti ion to the potential changes in the unit cell, showing that the single minimum of the time-averaged potential is centered at the paraelectric phase and off-centered at the ferroelectric phase.