Role of Symmetry, Geometry, and Termination Chemistry on Misfit Dislocation Patterns at Semicoherent Heterointerfaces

Abstract

Interfaces in semicoherent ceramic heterostructures are characterized by a network of misfit dislocations that plays a key role in dictating structural and functional properties in this important class of materials. Prediction of a misfit dislocation network structure, given the chemistries forming the heterointerface, remains a challenging problem that requires highly specialized experimental synthesis and characterization or computation-intensive atomistic simulations. Here, we present a heuristic approach that allows us to qualitatively predict the structure of misfit dislocation networks in semicoherent ionic heterostructures. The predictions within the proposed and validated approach are based entirely on elastic effects and the nature of electrostatic interactions across the interface and, therefore, do not require any input from explicit simulations. In addition to providing an intuitive and rational justification of misfit dislocation network structure in semicoherent ionic heterostructures, our approach is expected to complement experimental and simulation-based efforts targeted at determining and quantifying misfit dislocation patterns.

High-Throughput Prediction of Thermodynamic Stabilities of Dopant-Defect Clusters at Misfit Dislocations in Perovskite Oxide Heterostructures

“…A Burgers vector of b⃗ = ⟨100⟩ is predicted for SrO–ZrO 2 , TiO 2 –BaO, and SrO–BaO interfaces, whereas for the TiO 2 –ZrO 2 interface, a misfit dislocation structure with Burgers vector of b⃗ = ⟨110⟩ is predicted. This prediction is in agreement with the qualitative prediction reported using a heuristic approach . While experiments have reported perovskite–perovskite heterostructures with cube-on-cube epitaxy, the dependence of the misfit dislocation structure on interface layer chemistry is not well understood .…”

“…28,53 In cases where either STO or BZO is used to fabricate oxide heterostructures, understanding the role of dopants and defects in influencing the nanomaterial properties would be beneficial. To achieve this goal in the present study, we utilized atomistic simulations in conjunction with high-throughput computing to investigate the thermodynamic stabilities of thousands of dopant-defect clusters in the model system of STO/BZO heterostructure, 54 with an emphasis on misfit dislocations and interface region. We studied geometrically diverse clusters at SrO−BaO, SrO−ZrO 2 , BaO−TiO 2 , and ZrO 2 −TiO 2 interfaces having dissimilar misfit dislocation structures.…”

“…We studied geometrically diverse clusters at SrO−BaO, SrO−ZrO 2 , BaO−TiO 2 , and ZrO 2 −TiO 2 interfaces having dissimilar misfit dislocation structures. 54 The main goal of this work is to offer atomic scale insights pertaining to the thermodynamic preference of dopant-defect clusters and shed light on their behavior near differing misfit dislocation structures in STO/BZO heterostructures.…”

High-throughput prediction of oxygen vacancy defect migration near misfit dislocations in SrTiO3/BaZrO3 heterostructures

“…7,8 In cases where perovskite oxide heterostructures are implemented as model systems for SOFC electrolytes, knowledge of oxygen vacancy migration pathways in influencing the ionic transport would be beneficial. To achieve this goal, we used atomistic simulations in conjunction with high-throughput computing to predict thousands of activation energy barriers for oxygen vacancy migration in the model system of the STO/ BZO heterostructure, 60 with emphasis on misfit dislocations and the interface region. We studied oxygen vacancy migration pathways at SrO-ZrO 2 , BaO-TiO 2 , and ZrO 2 -TiO 2 interfaces having dissimilar misfit dislocation structures.…”

Order-Disorder Behavior at Thin Film Oxide Interfaces

“…45 The farreaching strain field around these dislocations (several nm) can lead to the formation of intricate and complex networks, which in turn possess unique chemical, transport, and radiation responses. [46][47][48][49][50][51] In addition to these extended defects, more localized cation defects can also easily form in response to the interface strain and charge state, depending on the choice of substrate and its surface termination. The similar size of multivalent cation species, coupled with the elevated temperatures used during deposition, provide ample opportunity for cation intermixing, which can completely alter the character of the interface.…”