Properties of Ferroelectric Nanodots Embedded in a Polarizable Medium: Atomistic Simulations

Prosandeev, S. A.; Bellaïche, L.

doi:10.1103/physrevlett.97.167601

Cited by 34 publications

(32 citation statements)

References 28 publications

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“…In the bigger rectangular dot, the dipole flux between the vortices is uniform, as in elongated cylinders 2 and in arrays of ferroelectric dots embedded in less polarizable media. 16 Short-range and elastic interactions are responsible for such antiphase orientation, since ͑as we will see in Sec. VI͒ the long-range dipole-dipole interaction favors a parallel orientation of the vortices.…”

Section: A Dipole Patternsmentioning

confidence: 98%

Characteristics and signatures of dipole vortices in ferroelectric nanodots: First-principles-based simulations and analytical expressions

Prosandeev

Bellaïche

2007

Phys. Rev. B

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Characteristics and signatures of dipole vortex in ferroelectric nanodots are determined via the use of first-principles-based simulations and by analytical developments. For instance, the dependency of such vortex on size, shape, material, and temperature is provided. Moreover, peculiar features associated with such vortex, such as unique behaviors of the inhomogeneous and homogeneous strains and of the induced electric fields, are revealed. Finally, energetics of interacting vortices is also discussed.

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Section: A Dipole Patternsmentioning

confidence: 98%

Characteristics and signatures of dipole vortices in ferroelectric nanodots: First-principles-based simulations and analytical expressions

Prosandeev

Bellaïche

2007

Phys. Rev. B

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“…They are: state (5) which is a vortex state characterized by a significantly negative G z but that, unlike state (1), is polarized and happens for the largest negative field values; [19] state (6) that differs from state (5) by having a much smaller polarization and, especially, by forming two vortices: one vortex that is reminiscent of state (5), and the second one that has nucleated inside the dot and that is not only of smaller dimension but also of opposite chirality than the first vortex. Such striking states can be classified as an antiferrotoroidic pair state [20]; state (7) that is also a vortex state as state (5), but of opposite sign for its G z and P y , and that occurs for the largest positive investigated fields; and state (8) that resembles state (6) once reversing the chiralities of both the large and small vortices. Figures 1(c) and 1(d) thus reveal that it is also possible to control the chirality of vortices by applying homogeneous fields in asymmetric ferroelectric nanorings [21], via the transition to intermediate states-as in ferromagnetic rings.…”

Section: Mads Clausen Institute For Product Innovation University Ofmentioning

confidence: 98%

Control of Vortices by Homogeneous Fields in Asymmetric Ferroelectric and Ferromagnetic Rings

et al. 2008

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Effective Hamiltonians have been used (i) to demonstrate that the shape asymmetry of ferromagnetic rings is essential to the recently discovered switching of the chirality of their vortices by homogeneous magnetic fields, via a transition into onion states; (ii) to reveal that an electric vortex can also be controlled by a homogeneous electric field in asymmetric ferroelectric nanorings, via the formation of antiferrotoroidic pair states rather than onion states; and (iii) to provide the fundamental reason that allows such control, namely, two new interaction energies involving a vector characterizing the asymmetry, the applied field, and the toroidal moment.Vortex states, in which the dipoles form a closure structure, have been discovered in small magnetic disks in the last seven years (see, e.g., Ref.[1] and references therein). Interestingly, vortex structures have also been recently predicted in another kind of dipolar systems of high importance, namely ferrolectrics [2]-when these latter are of nanoscale size and under open-circuit-like electric boundary condition [3] (i.e., for no or small screening of the polarization-induced surface charges). The existence of these vortices holds tremendous promise for nanotechnology. However, in order to fulfill such promise, one has to solve the challenging problem of controlling the vortices' chirality. As a matter of fact, magnetic and electric vortices cannot directly couple with homogeneous magnetic and electric fields, respectively [4 -7]. Alternative methods have thus been suggested for such control, ranging from simultaneously applying an electric and a magnetic field and taking advantage of their cross product [4] to the use of inhomogeneous fields [2,6]. Unfortunately, these methods are by no means trivial. This explains why the recent observation that the chirality of vortices can be switched by applying a homogeneous magnetic field in asymmetric magnetic disks is an important breakthrough (see Ref.[1] and references therein). Moreover, this switching involves peculiar intermediate states, namely, the so-called onion states [8], which makes it even more interesting. However, this recent observation also raises many important questions. For instance, the fundamental reason behind such switching is a mystery. Similarly, the precise role of the shape's asymmetry on that control remains unexplained. Furthermore, it is worthwhile to know if a homogeneous electric field can also affect the magnitude of electric vortices and switch their chirality in (asymmetric) ferroelectrics -which will make the control of vortices by homogeneous field a general phenomena in (asymmetric) dipolar systems. If such possibility indeed occurs, determining if onion, or even other, intermediate states are also involved in that switching is of high interest. The aims of this present Letter are to answer all the questions mentioned above, via the use of computational schemes.The height, and internal and external radii about the z axis (that lies along the [001] pseudocubic direction) of ou...

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“…These configurations were subsequently relaxed at 5 K. The resulting relaxed configurations feature a spontaneous polarization along the axial direction of the nanowire, co-occurring with flux-closure four-domain vortex structures of the cross-sectional polarization field in each of the wires with the assigned circulation. The latter in-plane vortex pattern within the wires corresponds to a tangential ordering against the interfaces whereby the depolarizing field experienced by the in-plane components is reduced [39]. We find that the (1-3) connectivity [33] of the considered nanocomposite structure hosts a polarization state possessing translational invariance along the axial direction of the wire.…”

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confidence: 83%

Frustration and Self-Ordering of Topological Defects in Ferroelectrics

2016

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Properties of Ferroelectric Nanodots Embedded in a Polarizable Medium: Atomistic Simulations

Cited by 34 publications

References 28 publications

Characteristics and signatures of dipole vortices in ferroelectric nanodots: First-principles-based simulations and analytical expressions

Characteristics and signatures of dipole vortices in ferroelectric nanodots: First-principles-based simulations and analytical expressions

Control of Vortices by Homogeneous Fields in Asymmetric Ferroelectric and Ferromagnetic Rings

Frustration and Self-Ordering of Topological Defects in Ferroelectrics

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