Atomistic simulation study of 〈1 1 0〉 dislocations in strontium titanate

Hirel, Pierre; Mrovec, Matous; Elsässer, Christian

doi:10.1016/j.actamat.2011.09.049

Cited by 40 publications

(48 citation statements)

References 38 publications

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“…The 〈1 1 0〉 dislocations dissociate into (collinear) partials following the Burgers vector reaction: 〈1 10 〉 → ½〈1 1 0〉 + ½〈1 1 0〉, partial dislocations being separated by an antiphase boundary (APB). The latter has been confirmed by theoretical calculations of the core structure of 〈1 1 0〉 dislocations in SrTiO 3 [13][14][15]. Deformed single crystal microstructure being predominantly composed of straight 〈1 1 0〉 screw dislocations, together with the general (albeit non-monotonic) increase in CRSS with decreasing temperature, are typical signs of lattice friction controlled plasticity in the low temperature regime A, characterised by stress-assisted thermally activated dislocation glide.…”

Section: Introductionmentioning

confidence: 61%

“…To compute V p as shown in Figure 2, we use the γ-surface calculations of Hirel et al [13], and u m is derived from the dislocation core structure provided by Hirel et al [14]. It yields a Peierls stress τ p = 500 GPa.…”

Section: Modelling the Kink-pair Mechanismmentioning

confidence: 99%

“…As a result, the interaction energy ΔE 1 , 2 between the partials ξ 1 and ξ 2 (involving the interaction between segments N and N' in Figure 1(b)) becomes: Table 1. elastic properties (shear modulus μ and Poisson ratio ν) of srTio 3 and dislocation core structure parameters of the 〈1 1 0〉{1 1 0} screw dislocation (as inferred from atomistic modelling [14]). b p is the modulus of the partial Burgers vector.…”

Section: Elastic Interaction Modelmentioning

confidence: 99%

“…stacking faults, dislocations) is of paramount importance. The mechanical behaviour of strontium titanate has turned out to be complex over a wide temperature range [5][6][7][8][9][10][11][12][13][14]. Despite its brittleness at high temperatures between 1050 and 1270 K [5,8], this oxide ceramic with a perovskite structure deforms in a ductile regime at temperatures below 1050 K, now commonly referred to as regime A [5][6][7][8]12].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On low temperature glide of dissociated 〈1 1 0〉 dislocations in strontium titanate

Ritterbex

Hirel

Carrez

2018

Philosophical Magazine

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An elastic interaction model is presented to quantify low temperature plasticity of SrTiO 3 via glide of dissociated 〈1 1 0〉{1 1 0} screw dislocations. Because 〈1 1 0〉 dislocations are dissociated, their glide, controlled by the kink-pair mechanism at T < 1050 K, involves the formation of kink-pairs on partial dislocations, either simultaneously or sequentially. Our model yields results in good quantitative agreement with the observed non-monotonic mechanical behaviour of SrTiO 3 . This agreement allows to explain the experimental results in terms of a (progressive) change in 〈1 1 0〉{1 1 0} glide mechanism, from simultaneous nucleation of two kinkpairs along both partials at low stress, towards nucleation of single kink-pairs on individual partials if resolved shear stress exceeds a critical value of 95 MPa. High resolved shear stress allows thus for the activation of extra nucleation mechanisms on dissociated dislocations impossible to occur under the sole action of thermal activation. We suggest that stress condition in conjunction with core dissociation is key to the origin of non-monotonic plastic behaviour of SrTiO 3 at low temperatures.

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Section: Introductionmentioning

confidence: 61%

Section: Modelling the Kink-pair Mechanismmentioning

confidence: 99%

Section: Elastic Interaction Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On low temperature glide of dissociated 〈1 1 0〉 dislocations in strontium titanate

Ritterbex

Hirel

Carrez

2018

Philosophical Magazine

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“…According to the studies by Thomas et al [34], Benedeck et al [35] and Hirel et al [36], the rigid-ion potential developed by Thomas et al [37] for STO behaves even better in comparing with experimental and ab initio data of elastic constants, lattice parameter, formation energy of defects and stacking faults energy than some shell-model potentials. Hirel et al [38] successfully used this potential in an atomistic simulation to study the mechanical behaviour of edge and screw dislocations in STO. In this work, the Thomas potential [34] is employed to derive the internal force density in the CAC model, which serves as a role for the constitutive relation in continuum mechanics.…”

Section: Computational Models and Simulation Results (A) Interatomic mentioning

confidence: 99%

Concurrent atomistic and continuum simulation of bi-crystal strontium titanate with tilt grain boundary

Yang

Chen

2015

Proc. R. Soc. A.

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In this paper, we present the development of a concurrent atomistic-continuum (CAC) methodology for simulation of the grain boundary (GB) structures and their interaction with other defects in ionic materials. Simulation results show that the CAC simulation allows a smooth passage of cracks through the atomistic-continuum interface without the need for additional constitutive rules or special numerical treatment; both the atomic-scale structures and the energies of the four different [001] tilt GBs in bicrystal strontium titanate obtained by CAC compare well with those obtained by existing experiments and density function theory calculations. Although 98.4% of the degrees of freedom of the simulated atomistic system have been eliminated in a coarsely meshed finite-element region, the CAC results, including the stress-strain responses, the GB-crack interaction mechanisms and the effect of the interaction on the fracture strength, are comparable with that of all-atom molecular dynamics simulation results. In addition, CAC simulation results show that the GBcrack interaction has a significant effect on the fracture behaviour of bi-crystal strontium titanate; not only the misorientation angle but also the atomic-level details of the GB structure influence the effect of the GB on impeding crack propagation.

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Beyond Coherent Oxide Heterostructures: Atomic‐Scale Structure of Misfit Dislocations

Dholabhai

Uberuaga

2019

Advcd Theory and Sims

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Nanoscale design of complex oxide heterostructures and thin films is imperative as they have significant promise in novel technological applications. A coherent interface is formed in oxide heterostructures with small mismatches, and the lattice mismatch is completely compensated by elastic strain. In semi-coherent oxide heterostructures, when an epitaxial layer is grown on the substrate above the critical thickness of the film, misfit dislocations are formed to mitigate the strain between the two materials with dissimilar lattice constants. Key properties of semi-coherent oxide heterostructures are influenced or even controlled by the presence of misfit dislocations. Therefore, it is critical to understand the atomic-scale structure of semi-coherent oxide heterostructures, specifically the structure of misfit dislocations that are ubiquitous at such heterointerfaces. Numerous state-of-the-art experiments have reported emergent phenomena at semi-coherent oxide heterostructures, wherein misfit dislocations play a crucial role. However, their atomic-scale and nanoscale structure is not always discernable from experiments. Due to large system sizes, computational studies dedicated to examining misfit dislocations in semi-coherent oxide heterostructures are still in their infancy. This review aims to summarize the recent advancements and challenges involved in computational studies elucidating the atomic-scale structure of misfit dislocations in semi-coherent oxide heterostructures and motivate future computational efforts.

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Atomistic simulation study of 〈1 1 0〉 dislocations in strontium titanate

Cited by 40 publications

References 38 publications

On low temperature glide of dissociated 〈1 1 0〉 dislocations in strontium titanate

On low temperature glide of dissociated 〈1 1 0〉 dislocations in strontium titanate

Concurrent atomistic and continuum simulation of bi-crystal strontium titanate with tilt grain boundary

Beyond Coherent Oxide Heterostructures: Atomic‐Scale Structure of Misfit Dislocations

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