Ferromagnetism induced by entangled charge and orbital orderings in ferroelectric titanate perovskites

Bristowe, Nicholas C.; Varignon, Julien; Fontaine, D.; Bousquet, Éric; Ghosez, Philippe

doi:10.1038/ncomms7677

Cited by 96 publications

(68 citation statements)

References 52 publications

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“…16 and 17, concluding that it is an ideal formalism to get past the typical shortcomings of semilocal functionals. Numerous papers have been published, based on the B1WC functional in several fields of physics, such has ferroelectrics 12,18 , ferromagnets 19 , bidimensional electron gas at oxide interfaces 20 or thermoeletrics 21,22 . The B1WC hybrid has demonstrated its ability to model magnetic systems, and has the advantage of being parameter free.…”

Section: A Computational Detailsmentioning

confidence: 99%

Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

et al. 2015

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Section: A Computational Detailsmentioning

confidence: 99%

Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

et al. 2015

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“…This concept is related to an unusual coupling of lattice modes, giving rise in the free energy expansion to a trilinear term −λPR 1 R 2 linking the polar motion P to two independent nonpolar distortions R 1 and R 2 . Such a coupling was identified in various layered perovskites [8,9,[12][13][14][15], metal-organic framework [16,17], and can even appear in bulk ABO 3 perovskites [18,19]. Interestingly, in Ruddlesden-Popper compounds [9,20] and ABO 3 =A 0 BO 3 superlattices [21], this trilinear coupling appeared as a practical way to achieve electric control of nonpolar antiferrodistortive (AFD) motions associated with the rotation of the oxygen octahedra (i.e., monitoring P with an electric field will directly and sizeably tune the nonpolar modes R 1 and/or R 2 ).…”

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confidence: 99%

Electric Field Control of Jahn-Teller Distortions in Bulk Perovskites

2016

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The Jahn-Teller distortion, by its very nature, is often at the heart of the various electronic properties displayed by perovskites and related materials. Despite the Jahn-Teller mode being nonpolar, we devise and demonstrate, in the present Letter, an electric field control of Jahn-Teller distortions in bulk perovskites. The electric field control is enabled through an anharmonic lattice mode coupling between the Jahn-Teller distortion and a polar mode. We confirm this coupling and quantify it through first-principles calculations. The coupling will always exist within the Pb2 1 m space group, which is found to be the favored ground state for various perovskites under sufficient tensile epitaxial strain. Intriguingly, the calculations reveal that this mechanism is not only restricted to Jahn-Teller active systems, promising a general route to tune or induce novel electronic functionality in perovskites as a whole. DOI: 10.1103/PhysRevLett.116.057602 Perovskite ABO 3 compounds, and related materials, are fascinating systems exhibiting a diverse collection of properties, including ferroelectricity, magnetism, orbitalordering, metal-insulator phase transitions, superconductivity, and thermoelectricity [1]. Despite the wide range of physical behavior, a common point at the origin of many of them can be identified as being the Jahn-Teller (JT) distortion [2,3]. The Jahn-Teller distortion is, itself, intimately linked to electronic degrees of freedom, since, traditionally, it manifests to remove an electronic degeneracy, opening a band gap and favoring a particular orbital ordering which, in turn, can affect magnetic ordering. Furthermore, it plays an important role, for example, in colossal magnetoresistance phenomena in doped manganites [4], superconductivity [5,6], or the strong electronic correlation observed in the thermoelectric NaCoO 2 family [7].It would be highly desirable, for device functionality, for example, to be able to tune the Jahn-Teller distortion and, hence, its corresponding electronic properties, with the application of an external electric field. However, JahnTeller distortions are nonpolar and, hence, not directly tunable with an electric field.Recently, the concept of "hybrid improper ferroelectricity" has emerged within the community of oxide perovskites [8][9][10][11]. This concept is related to an unusual coupling of lattice modes, giving rise in the free energy expansion to a trilinear term −λPR 1 R 2 linking the polar motion P to two independent nonpolar distortions R 1 and R 2 . Such a coupling was identified in various layered perovskites [8,9,[12][13][14][15], metal-organic framework [16,17], and can even appear in bulk ABO 3 perovskites [18,19]. Interestingly, in Ruddlesden-Popper compounds [9,20] and ABO 3 =A 0 BO 3 superlattices [21], this trilinear coupling appeared as a practical way to achieve electric control of nonpolar antiferrodistortive (AFD) motions associated with the rotation of the oxygen octahedra (i.e., monitoring P with an electric field will directly and sizeably...

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“…[6][7][8] In perovskite transition metal (TM) oxide (ABO 3 ) n (A BO 3 ) m (001) superlattices, the layered cation ordering lowers the symmetry from cubic to tetragonal and breaks up-down symmetry across BO 2 layers. Control of the TM d-orbital occupancy through choice of A cations and layer thicknesses to obtain a mixed valence leads to charge disproportionation and long-range charge ordering [9][10][11][12]. As we will discuss further below, layered charge ordering breaks the up-down symmetry across the AO and A O layers.…”

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confidence: 99%

Charge-Order-Induced Ferroelectricity inLaVO3/SrVO3Superlattices

2017

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The structure and properties of the 1:1 superlattice of LaVO3 and SrVO3 are investigated with a firstprinciples density-functional-theory-plus-U (DFT+U ) method. The lowest energy states are antiferromagnetic charge-ordered Mott-insulating phases. In one of these insulating phases, layered charge ordering combines with the layered cation ordering to produce a polar structure with nonzero spontaneous polarization normal to the interfaces. This polarization is produced by electron transfer between the V 3+ and V 4+ layers, and is comparable to that of conventional ferroelectrics. The energy of this polar state relative to the nonpolar ground state is only 3 meV per vanadium. Under tensile strain, this energy difference can be further reduced, suggesting that the polar phase can be induced by applied electric field, yielding an antiferroelectric double-hysteresis loop. If the system does not switch back to the nonpolar state on removal of the field, a ferroelectric-type hysteresis loop could be observed. PACS numbers: 73.21.Cd, 75.25.Dk, 77.55.Px The investigation of novel mechanisms for ferroelectricity has attracted much interest in recent years, especially in the search for ferroelectrics with properties, such as ferromagnetism, that are contraindicated by the mechanism driving ferroelectricity in the prototypical perovskite titanates [1]. One approach, proposed by Khomskii [2,3] is to combine two symmetry-breaking orderings, neither of which separately lift inversion symmetry, to generate a switchable polar structure [4]. The specific orderings discussed by Khomskii are sitecentered charge ordering and bond-centered charge ordering. Ferroelectricity and multiferroelectricity induced by charge order have been proposed and reported in various magnetites, manganates, and charge transfer organic salts [2,3,5]. In some of these materials, the polarization is dominated by the electron transfer producing the charge order rather than by ionic displacements, leading to the term "electronic ferroelectricity." [6][7][8] In perovskite transition metal (TM) oxide (ABO 3 ) n (A BO 3 ) m (001) superlattices, the layered cation ordering lowers the symmetry from cubic to tetragonal and breaks up-down symmetry across BO 2 layers. Control of the TM d-orbital occupancy through choice of A cations and layer thicknesses to obtain a mixed valence leads to charge disproportionation and long-range charge ordering [9-12]. As we will discuss further below, layered charge ordering breaks the up-down symmetry across the AO and A O layers. Thus, the combination of these two symmetry-breaking orderings (TM site-centered charge ordering and layered cation ordering) can generate a switchable polar structure with polarization normal to the layers.A 1:1 superlattice composed of LaVO 3 and SrVO 3 is a promising candidate for this type of charge-order-induced ferroelectricity. The low temperature phases of orthorhombic LaVO 3 and cubic SrVO 3 are antiferromagnetic Mottinsulating and correlated metallic, respectively [9,[13][14][15]. When they f...

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Ferromagnetism induced by entangled charge and orbital orderings in ferroelectric titanate perovskites

Cited by 96 publications

References 52 publications

Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

Electric Field Control of Jahn-Teller Distortions in Bulk Perovskites

Charge-Order-Induced Ferroelectricity inLaVO3/SrVO3Superlattices

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