Origin of ferroelectricity in LiTaO3 and LiNbO3; LAPW total energy calculations

Inbar, Iris; Cohen, R. E.

doi:10.1080/00150199508221829

Cited by 17 publications

(8 citation statements)

References 37 publications

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“…The largest relative displacements are those of Bi relative to O owing to the presence of stereochemically active Bi lone pair [101]. The off-center displacements are noticeably larger compared to those in nonlone-pair-active perovskite ferroelectrics such as BaTiO 3 or LiNbO 3 [64,102], but are consistent with those observed in other Bi-based perovskites [62].…”

Section: H Spontaneous Polarizationsupporting

confidence: 68%

Theoretical investigation of magnetoelectric behavior inBiFeO3

et al. 2006

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The magnetoelectric behavior of BiFeO3 has been explored on the basis of accurate density functional calculations. We are able to predict structural, electronic, magnetic, and ferroelectric properties of BiFeO3 correctly without including any strong correlation effect in the calculation. Unlike earlier calculations, the equilibrium structural parameters are found to be in very good agreement with the experimental findings. In particular, the present calculation correctly reproduced experimentally-observed elongation of cubic perovskite-like lattice along the [111] direction. At high pressure we predicted a pressure-induced structural transition from rhombohedral (R3c) to an orthorhombic (P nma) structure. The total energy calculations at expanded lattice show two lower energy ferroelectric phases (with monoclinic Cm and tetragonal P 4mm structures), closer in energy to the ground state phase. Spin-polarized band-structure calculations show that BiFeO3 will be an insulator in A-and G-type antiferromagnetic phases and a metal in C-type antiferromagnetic, ferromagnetic configurations, and in the nonmagnetic state. Chemical bonding in BiFeO3 has been analyzed using partial density-of-states, charge density, charge transfer, electron localization function, Born-effective-charge tensor, and crystal orbital Hamiltonian population analyses. Our electron localization function analysis shows that stereochemically active lone-pair electrons are present at the Bi sites which are responsible for displacements of the Bi atoms from the centro-symmetric to the noncentrosymmetric structure and hence the ferroelectricity. A large ferroelectric polarization of 88.7 µC/cm 2 is predicted in accordance with recent experimental findings, but differing by an order of magnitude from earlier experimental values. The strong spontaneous polarization is related to the large values of the Born-effective-charges at the Bi sites along with their large displacement along the [111] direction of the cubic perovskite-type reference structure. Our polarization analysis shows that partial contributions to polarization from the Fe and O atoms almost cancel each other and the net polarization present in BiFeO3 mainly (> 98%) originates from Bi atoms. We found that the large scatter in experimentally reported polarization values in BiFeO3 is associated with the large anisotropy in the spontaneous polarization.

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Section: H Spontaneous Polarizationsupporting

confidence: 68%

Theoretical investigation of magnetoelectric behavior inBiFeO3

et al. 2006

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“…These are indeed not perovskites, but belong to the ilmenite structure type. Both are ferroelectric at room temperature, owing to a paraelectric to ferroelectric transition ( R ‐3c → R 3c) at 1480 K and 950 K respectively . Not only do they exhibit very high Curie temperatures for ferroelectricity, but the magnitude of the polarization is also very high.…”

Section: The Current Toolboxmentioning

confidence: 99%

Functional Perovskites by Atomic Layer Deposition – An Overview

Sønsteby

Fjellvåg

Nilsen

2017

Adv Materials Inter

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properties in thin film complex oxides and their heterostructures is still in its infancy.Functional perovskite oxide thin films have traditionally been deposited by physical, high temperature techniques, such as molecular beam epitaxy (MBE) and pulsed laser deposition (PLD). While these methods can provide films of very high structural quality, they do not offer deposition of conformal film on complex structures while maintaining control of stoichiometry. Chemical deposition techniques were long thought unsuitable for deposition of complex systems with high structural quality. This has changed dramatically over the last two decades. One of the most important techniques to emerge in this area has been atomic layer deposition (ALD).In this short review we aim to summarize the perovskite and ABO 3 -oxides, down to the ilmenite structure, that have been deposited using the ALD technique. The review includes work done over the last 20 years, and covers all oxide perovskites with ferromagnetic, piezoelectric and ferroelectric functionality known to have been deposited by ALD ( Table 1). The origin of the properties in these specific structures is briefly discussed, followed by a complete listing of the known systems. Perovskite heterostructures with new properties and combinations of properties are brought up, before thoughts on possible future work in the field concludes the paper. Why Atomic Layer Deposition?The ALD technique was pioneered independently in both Russia and Finland during the 1960s and 70s, and its history was thoroughly described by Puurunen in 2014. [4] The technique has been comprehensively discussed in several review papers over the last years. The first commercial application was to deposit zinc sulfide, used for electroluminescent display panels. The number of materials with known deposition routes was very limited for the first 20 years, before it exploded in the 1990s and still continues to grow. At the time of the review written by Miikkulainen et al. in 2013, binary oxides of most of the natural elements had been reported, as well as many nitrides, sulfides and fluorides (Figure 2). [5] As the community has embraced the possibility of growing epitaxial films of high chemical and structural quality, systems that are even more complex have been deposited, including materials with ternary, quaternary and even quinary compositions.The advantages and drawbacks of ALD as a thin film deposition technique have been reviewed several times the The last 20 years have seen a massive increase in reports on complex oxides with functional properties synthesized by atomic layer deposition (ALD). Many of these compounds have perovskite or perovskite-related structures, and exhibit a range of electric and magnetic properties. This short review summarizes the current status of functional perovskites and ABO 3 compounds down to the ilmenite structure prepared by ALD, focusing on ferromagnetism and ferro-and piezoelectricity. All perovskite-related compounds known to have been deposited by ALD down to the ilmeni...

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“…Previously we studied the difference between the self-consistent charge densities and charge densities computed using overlapping ions with the PIB model for both LiTaO 3 and LiNbO 3 in the ferroelectric phase 65 . In the PIB model which is a non-empirical ionic These results are consistent with the energetics and electronic structures results, all pointing to the same conclusion that the driving mechanism behind the ferroelectric instability in the LiNb(Ta)O 3 systems is the hybridization between the d states on the transition metal atoms and the 2p states on the oxygens.…”

Section: Comparison To the Perovskitesmentioning

confidence: 99%

Comparison of the electronic structures and energetics of ferroelectricLiNbO3andLiTaO3
Inbar
¹
,
Cohen
²

1996
Phys. Rev. B
Self Cite
157
11
91
0
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Extensive LAPW frozen phonon calculations were performed in order to understand the origin of ferroelectricity in LiTaO 3 and LiNbO 3 . Displacement of the Li atoms alone results in an anharmonic single well, whereas displacements of oxygen and lithium together result in deep double wells, much deeper than the transition temperatures, T C . This is contrary to current theories which model the underlying potential as a triple well potential for the lithium atoms. Our results support an order-disorder model for the oxygen atoms as the driving mechanism for the ferroelectric instability. Oxygen displacements alone against the transition metal atoms result in shallower double wells as a result of oxygen-lithium overlap so that the lithium and oxygen displacements are strongly coupled . We find large hybridization between the oxygens and the transition metal atoms. Thus ferroelectricity in the Li(Nb,Ta)O 3 system is similar in origin to ferroelectricity in the perovskites. We also find that the electronic structures of LiTaO 3 and LiNbO 3 are very similar and hardly 1 change during the phase transition.

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Origin of ferroelectricity in LiTaO3 and LiNbO3; LAPW total energy calculations

Cited by 17 publications

References 37 publications

Theoretical investigation of magnetoelectric behavior inBiFeO3

Theoretical investigation of magnetoelectric behavior inBiFeO3

Functional Perovskites by Atomic Layer Deposition – An Overview

Comparison of the electronic structures and energetics of ferroelectricLiNbO3andLiTaO3
Inbar
¹
,
Cohen
²

1996
Phys. Rev. B
Self Cite
157
11
91
0
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Origin of ferroelectricity in LiTaO3 and LiNbO3; LAPW total energy calculations

Cited by 17 publications

References 37 publications

Theoretical investigation of magnetoelectric behavior inBiFeO3

Theoretical investigation of magnetoelectric behavior inBiFeO3

Functional Perovskites by Atomic Layer Deposition – An Overview

Comparison of the electronic structures and energetics of ferroelectricLiNbO3andLiTaO3Inbar1, Cohen2 1996Phys. Rev. BSelf Cite15711910View full textAdd to dashboardCite

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Comparison of the electronic structures and energetics of ferroelectricLiNbO3andLiTaO3
Inbar
¹
,
Cohen
²

1996
Phys. Rev. B
Self Cite
157
11
91
0
View full text Add to dashboard Cite