Polarization Screening Mechanisms at La_0.7Sr_0.3MnO₃–PbTiO₃ Interfaces

Abstract

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3D Reconstruction of Sawtooth 180° Tail‐to‐Tail Domain Walls in Single Crystal BiFeO3

“…Figure 5c shows a map of −𝛿 FB magnitudes obtained from on the ADF-STEM image of Figure 5a 2D Gaussian fitting. [5,16] The result confirms that −𝛿 FB reverses direction across the DW and has roughly the same magnitude of about 40 pm in the two domains, in good accordance with the theoretical value of 41 pm. The correlation between the CDW bands in Figure 5b,c is quite poor; while they appear very diffuse in the ABF image, they present as sharp, but irregular, DWs in the −𝛿 FB map.…”

Negative Capacitance and Switching Dynamics Control Via Non-Ferroelectric Elements

“…Taking into account that a typical insulator has a dielectric constant of about 10, and the insulator layer capacitance should be an order of magnitude higher than the ferroelectric layer, the resulting insulator thickness should be roughly 100 times lower than that of the ferroelectric layer. Another example is the ultra-thin ferroelectric layers where spontaneous polarization has been detected, but switching is very difficult to achieve. , Decreasing the thickness of the ferroelectric layer is equivalent to increasing the FE capacitance, which becomes comparable to the capacitance of the electrode interfaces as it is deduced from impedance spectroscopy (Supporting Information Section 3).…”

“…Another example is the ultra-thin ferroelectric layers where spontaneous polarization has been detected, but switching is very difficult to achieve. 48,49 Decreasing the thickness of the ferroelectric layer is equivalent to increasing the FE capacitance, which becomes comparable to the capacitance of the electrode interfaces as it is deduced from impedance spectroscopy (Supporting Information Section 3).…”

Local Ionic Displacements and Polarization at the Paraelectric‐Ferroelectric Heterointerface: Effect of Octahedral Distortion

“…The perovskite structure contains A/B sublattices and a flexible BO 6 octahedral framework, and both of them can be adapted under the interfacial strain and take important roles in the functional structures and properties in ferroelectric perovskite oxide thin films. [ 12,13 ] The interfacial strain can govern the A/B sublattice mismatch between the substrate and the film and can also distort the A/B sublattices of the film away from the structure existing in the bulk materials. [ 14 ] For example, epitaxial BiFeO 3 film goes through a sequent phase transition from rhombohedral ( R )‐to‐monoclinic ( M A )‐to‐monoclinic ( M C )‐to‐tetragonal ( T ) by controlling the epitaxial strain alone.…”

“…In general, the displacement of cations between A and B sites may be not capable to represent the spontaneous polarization directly if the BO 6 octahedra deviate from the ideal positions and shapes or the mass center of the octahedron is not that of A or B-site atoms in the perovskite unit cell, since the spontaneous polarization stems from the separation of the charge center between A/B-site cations and oxygen anions.The perovskite structure contains A/B sublattices and a flexible BO 6 octahedral framework, and both of them can be adapted under the interfacial strain and take important roles in the functional structures and properties in ferroelectric perovskite oxide thin films. [12,13] The interfacial strain can govern the A/B sublattice mismatch between the substrate and the film and can also distort the A/B sublattices of the film away from the structure existing in the bulk materials. [14] For At the ferroelectric ABO 3 perovskite heterointerface, the broken translational symmetry significantly alters the octahedral network and cation sublattices.…”