Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

J Kaczkowski

doi:10.1007/s10853-016-0211-2

J Kaczkowski

Open Access

https://doi.org/10.1007/s10853-016-0211-2

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Abstract

High-pressure behavior of BiGaO3 has been investigated from 0 to 20 GPa using density functional theory. It is found that BiGaO3 undergoes a pressure-induced first-order phase transition from pyroxene (Pcca) to monoclinic (Cm) at 3.5 GPa, and then to rhombohedral (R3c) at 5.2 GPa, and finally to orthorhombic (Pnma) structure at 7.4 GPa. The first phase transition (Pcca → Cm) agrees well with the experimental results. At 5.2 GPa the possible coexistence of three ferroelectric phases, i.e., monoclinic Cm, tetragonal P4mm, and rhombohedral R3c has been predicted. The calculated values of spontaneous polarization for these phases are of 124.87, 123.48, 88.75 μC/cm2 for Cm, P4mm, and R3c, respectively.

Highlights

In recent years, the Bi-based perovskites have attracted an increasing interest as a less-toxic alternative to the most widely used ferroelectric material, lead zirconate titanate [1, 2]
The cell shape and internal atomic positions were optimized within GGA with the Perdew– Burke–Ernzerhof (GGA-PBE) functional [26] and local density approximation (LDA) [27]
We compare the total energies of fully optimized aforementioned phases of BiGaO3 at ambient pressure within both generalized gradient and local density approximations

Summary

Introduction

The Bi-based perovskites have attracted an increasing interest as a less-toxic alternative to the most widely used ferroelectric material, lead zirconate titanate [1, 2]. BiGaO3 has been studied extensively since the first theoretical report [3], in which large ferroelectric polarization was predicted with the value of 151.9 lC/cm for tetragonal ground-state structure (space group P4mm). The coexistence of polar rhombohedral (space group R3c) and monoclinic (space group Cm) phases was observed in solid solution BiFe1-xGaxO3 at x = 0.1 [6] and x = 0.2–0.4 [7] and BiCr1-xGaxO3 at x = 0.8 [7] For these solid solutions large values of spontaneous polarization were predicted using the point charge model, i.e., 58 lC/cm for BiGa0.4Cr0.6 O3, 116 lC/cm for BiGa0.4Fe0.6O3, and 102 lC/cm

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