Anomalous toughening in nanoscale ferroelectrics with polarization vortices

Lich, Le Van; Shimada, Takahiro; Nagano, Koyo; Yu, Hongjun; Wang, Jie; Huang, Kai; Kitamura, Takayuki

doi:10.1016/j.actamat.2014.12.056

Cited by 40 publications

(8 citation statements)

References 67 publications

(121 reference statements)

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“…Domains are regions of a ferroelectric crystal with uniform polarization. The arrangement, or pattern of these domains is of great importance in determining the properties of a ferroelectric at the nanoscale [1][2][3][4][5][6][7]. For example, the effective piezoelectric coefficients depend upon the fractions of different domain types present [6], and enhanced actuation can be achieved by using specific domain patterns [7].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale periodic domain patterns in tetragonal ferroelectrics: A phase-field study

2016

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Ferroelectrics form domain patterns that minimize their energy subject to imposed boundary conditions. In a linear, constrained theory, that neglects domain wall energy, periodic domain patterns in the form of multi-rank laminates can be identified as minimum-energy states. However, when these laminates (formed in a macroscopic crystal) comprise domains that are a few nanometers in size, the domain-wall energy becomes significant, and the behaviour of laminate patterns at this scale is not known. Here, a phase-field model, which accounts for gradient energy and strain energy contributions, is employed to explore the stability and evolution of the nanoscale multi-rank laminates. The stress, electric field, and domain wall energies in the laminates are computed. The effect of scaling is also discussed. In the absence of external loading, stripe domain patterns are found to be lower energy states than the more complex, multi-rank laminates, which mostly collapse into simpler patterns. However, complex laminates can be stabilized by imposing external loads such as electric field, average strain and polarization. The study provides insight into the domain patterns that may form on a macroscopic single crystal but comprising of nanoscale periodic patterns, and on the effect of external loads on these patterns. arXiv:1803.06564v1 [cond-mat.mtrl-sci]

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Section: Introductionmentioning

confidence: 99%

Nanoscale periodic domain patterns in tetragonal ferroelectrics: A phase-field study

2016

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“…For investigations of ferroelectric polarization textures and their behavior under electric and mechanical fields, we employ the phase field modeling, − in which the electric enthalpy ψ of the nanowires is expressed as − ψ = ψ Landau + ψ grad + ψ Elas + ψ Elec where ψ Landau , ψ Grad , ψ Elas , and ψ Elec are Landau (or polarization), gradient, elastic, and electrostatic energy densities, respectively. The expression of the Landau energy density is given by ψ Landau = α 1 ( p 1 2 + p 2 2 + p 3 2 ) + α 11 ( p 1 4 + p 2 4 + p 3 4 ) + α 12 ( p 1 2 p 2 2 + p 1 2 p 3 2 + p 2 2 …”

Section: Methodsmentioning

confidence: 99%

Theoretical Studies on Controlling the Chirality of Helical Polarization Vortices in Ferroelectric Nanowires: Implications for Reconfigurable Electronic Devices

Lich

Nguyen

Dinh

et al. 2022

ACS Appl. Nano Mater.

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Chiral polarization textures in ferroelectric nanosystems have attracted growing attention following the recent progress in nanomagnetism. Despite their growing interest, a clear understanding of the mechanisms for controlling the formation and behavior of topological polarization textures in these systems has remained elusive. In this study, we present the first theoretical investigation of polarization textures in BaTiO3/BaZr0.05Ti0.95O3 nanowires. Several topological polarization textures are formed as a result of the combined geometrical confinement and size effects. Interestingly, we observe a stable helical polarization vortex texture that possesses spiral-like precession of a vortex core around the central line of the nanowire. The formation of this helical polarization vortex originates from the balance effect between the geometrical confinement and dipole–dipole interactions of different ferroelectric phases that are present in the nanowires. The chirality of the helical polarization vortex can be controlled by external electric and mechanical fields. The findings pave a pathway for creating and controlling topological polar textures in ferroelectric nanowires toward the development of reconfigurable electronic devices.

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“…The formation of polarization vortex in a free-standing ferroelectric nanodot with square crossed-section is investigated. To intentionally form spontaneous polarization vortex in the nanodot, the dimensions of nanodots are set within a range from several to tens of nanometers, which takes into account the strong depolarization field at free surfaces of nanodot [10,26,55]. Therefore, the thickness of nanodots is prepared at 10 nm, while the width and length are set to be 16 nm.…”

Section: Temporal Evolution Of Polarization Structure In Ferroelectri...mentioning

confidence: 99%

“…To circumvent this difficulty, a distinct strategy is essential. The recently developed phase field model [22][23][24][25] based on the Ginzburg-Landau theory has substantially provided an unprecedented look at the formation and behavior of polarization in nanoscale ferroelectrics [22] and successfully reproduced the polarization vortices in nanoscale ferroelectrics [26][27][28][29]. In comparison to DFT calculations, the phase field model is more effective and can be applied for complex structures of ferroelectrics in a wide range from nanoscale to macroscale.…”

Section: Introductionmentioning

confidence: 99%

An efficient space-time phase field discretization for ferroelectrics

Lich¹,

Bui²,

Nguyen³

et al. 2020

Modelling Simul. Mater. Sci. Eng.

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Recent developments of phase field model based on the Ginzburg-Landau theory have provided an unprecedented look at the formation of polarization domain structures and rich phenomena of polarization behaviors in nanoscale ferroelectrics under electrical and mechanical multi-fields. However, the phase field simulations are often computationally expensive. One of the major reasons behind this inefficiency is due to the complex spatio-temporal effects on the dynamical behavior of polarization. In this work, an efficient scheme with error control and adaptive time-stepping is introduced to the phase field model in the context of Ginzburg-Landau theory. The proposed time adaptivity algorithm is based on the discrete maximum norm of the difference in numerical solutions at three consecutive time steps. In addition, the energy stability of the proposed scheme is demonstrated. Several benchmarks of convergence tests are presented to validate the model. The performance of proposed technique is illustrated through numerical examples involving behaviors of polarization in complex ferroelectric nanostructures in three dimensions.

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Anomalous toughening in nanoscale ferroelectrics with polarization vortices

Cited by 40 publications

References 67 publications

Nanoscale periodic domain patterns in tetragonal ferroelectrics: A phase-field study

Nanoscale periodic domain patterns in tetragonal ferroelectrics: A phase-field study

Theoretical Studies on Controlling the Chirality of Helical Polarization Vortices in Ferroelectric Nanowires: Implications for Reconfigurable Electronic Devices

An efficient space-time phase field discretization for ferroelectrics

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