Direct molecular dynamics simulation of electrocaloric effect in BaTiO3

TL;DR

This study uses molecular dynamics simulations to analyze the electrocaloric effect in BaTiO3 across various temperatures and electric fields, revealing the influence of electric field strength and crystal orientation on temperature change.

Contribution

It introduces first-principles based effective Hamiltonian molecular dynamics methods to simulate the electrocaloric effect in BaTiO3 over a wide temperature and electric field range.

Findings

Large adiabatic temperature change observed at Curie temperature.

Higher electric fields broaden the temperature range of significant ECE.

Electric field orientation affects the magnitude of ECE, with [001] being most effective.

Abstract

The electrocaloric effect (ECE) in BaTiO3 is simulated using two different first-principles based effective Hamiltonian molecular dynamics methods. The calculations are performed for a wide range of temperatures (30--900 K) and external electric fields (0--500 kV/cm). As expected, a large adiabatic temperature change, Delta-T, at the Curie temperature, T_C, is observed. It is found that for single crystals of pure BaTiO3, the temperature range where a large Delta-T is observed is narrow for small external electric fields (<50 kV/cm). Large fields (>100 kV/cm) may be required to broaden the effective temperature range. The effect of crystal anisotropy on the ECE Delta-T is also investigated. It is found that applying an external electric field along the [001] direction has a larger ECE than those along the [110] and [111] directions.