Quantum properties of charged ferroelectric domain walls

Sturman, B.; Podivilov, E. V.; Stepanov, M. M.; Tagantsev, A. K.; Setter, N.

doi:10.1103/physrevb.92.214112

Cited by 24 publications

(26 citation statements)

References 37 publications

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“…3b) so that the potential decays far from the core. The width of the core is close to the wall width w, obtained with neglected traps, 80,87 while the tail length ' is much larger than w. For a H-H CDW (electron screening), the most important parameters-the width w e , the tail length ' e , and…”

Section: Theoretical Insights Into Cdw Propertiessupporting

confidence: 53%

“…A more advanced treatment of 180°SCDWs was offered by combining the Landau theory with the self-consistent Hartree approximation for screening electrons. 87 It has revealed a generic discrete quantum structure of CDWs and the condition for employment of the Thomas-Fermi approximation. Specifically, the electron motion perpendicular to the walls is quantized such that the electron energy spectrum exhibits a finite number of subbands related to free electron propagation along the wall (Fig.…”

Section: Theoretical Insights Into Cdw Propertiesmentioning

confidence: 99%

“…Experiments show that the effective trap concentration N t varies around 10 17 cm −3 in nominally undoped ferroelectrics. 88 It was shown analytically and numerically 84,87 that the presence of traps leads to modification of the SCDW structure: The wall consists of a relatively narrow core, containing most of the screening charge, and some tails ( Fig. 3b) so that the potential decays far from the core.…”

Section: Theoretical Insights Into Cdw Propertiesmentioning

confidence: 99%

“…This estimate has a simple interpretation: for the full screening, one should transfer 2P 0 /e electrons [per unit area] across the bandgap, paying the energy penalty E g /e per electron. A more elaborate treatment 87 provides expressions for the formation energies for the electron (W e ) and hole (W h ) screened CDWs:…”

Section: Inwall Wavevector Kmentioning

confidence: 99%

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Physics and applications of charged domain walls

Bednyakov

Sturman

Sluka³

et al. 2018

npj Comput Mater

164

158

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The charged domain wall is an ultrathin (typically nanosized) interface between two domains; it carries bound charge owing to a change of normal component of spontaneous polarization on crossing the wall. In contrast to hetero-interfaces between different materials, charged domain walls (CDWs) can be created, displaced, erased, and recreated again in the bulk of a material. Screening of the bound charge with free carriers is often necessary for stability of CDWs, which can result in giant two-dimensional conductivity along the wall. Usually in nominally insulating ferroelectrics, the concentration of free carriers at the walls can approach metallic values. Thus, CDWs can be viewed as ultrathin reconfigurable strongly conductive sheets embedded into the bulk of an insulating material. This feature is highly attractive for future nanoelectronics. The last decade was marked by a surge of research interest in CDWs. It resulted in numerous breakthroughs in controllable and reproducible fabrication of CDWs in different materials, in investigation of CDW properties and charge compensation mechanisms, in discovery of light-induced effects, and, finally, in detection of giant two-dimensional conductivity. The present review is aiming at a concise presentation of the main physical ideas behind CDWs and a brief overview of the most important theoretical and experimental findings in the field.

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Section: Theoretical Insights Into Cdw Propertiessupporting

confidence: 53%

Section: Theoretical Insights Into Cdw Propertiesmentioning

confidence: 99%

Section: Theoretical Insights Into Cdw Propertiesmentioning

confidence: 99%

Section: Inwall Wavevector Kmentioning

confidence: 99%

See 2 more Smart Citations

Physics and applications of charged domain walls

Bednyakov

Sturman

Sluka³

et al. 2018

npj Comput Mater

164

158

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“…DWC in lithium niobate (LiNbO 3 :LNO) so far was reported to happen under photoexcitation only. [20] All these microscopic theories aim at predicting and quantifying the relevant local-scale domain wall parameters, i.e., the DW formation energy, the free charge distribution, and the DW conductivity. [20] All these microscopic theories aim at predicting and quantifying the relevant local-scale domain wall parameters, i.e., the DW formation energy, the free charge distribution, and the DW conductivity.…”

mentioning

confidence: 99%

Resistor Network Modeling of Conductive Domain Walls in Lithium Niobate

Wolba

Seidel

Cazorla

et al. 2017

Adv Elect Materials

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devices, [10] and the fundamental inspection by theory and experiment.While ferroelectrics constitute wideband gap semiconductors with good insulating properties, their DWs may possess a significantly increased electrical conductivity, as is of central focus in the work here. This so-called domain wall conductivity (DWC) has been reported first for multiferroic bismuth ferrite [11] and lead-zirconate-titanate [12] thin films, followed by research on (improper) erbium manganite [13] and barium titanate [14] bulk ferroelectric crystals. DWC in lithium niobate (LiNbO 3 :LNO) so far was reported to happen under photoexcitation only. [15,16] However, recent experiments by Godau et al. [17] on LNO single crystals (sc) have shown that reshaping the DW to larger inclination angles by applying a dedicated electrical tuning protocol enhances DWC by 3-4 orders of magnitude, and gives rise to DW currents in the upper µA range at room temperature and in the dark.Theoretical approaches applied to explain the increased DWC in these materials include phenomenological Landau [18] and Landau-Ginzburg-Devonshire theory, [19] and more recently also the combination of quantum mechanics with phenomenological Landau theory. [20] All these microscopic theories aim at predicting and quantifying the relevant local-scale domain wall parameters, i.e., the DW formation energy, the free charge distribution, and the DW conductivity. Nevertheless, it is difficult to compare the outcomes of such microscopic theories directly to experimental data, as the latter generally is based on macroscopic quantities. In contrast, our resistor network (RN) approach provides a clue link to experiments, in spite of being nonpredictive (i.e., as it requires some initial experimental input). Hence, our results can be directly compared to the local currents flowing within the DW as measured for instance by conductive atomic force microscopy (cAFM). The simple picture of a RN thus elegantly complements the microscopic theories of DWC. MethodsFor the modeling a 2D network of linear, Ohmic resistors (see Figure 1a) was used, that was carefully crafted on the basis of the DW's inclination angle distribution. Resistor networks (RN) have already been applied impressively for modeling a Here the concept of a 2D resistor network (2D RN) is applied in order to model the electrical conductivity along sheet-like domain walls (DWs) in single crystalline lithium niobate (sc-LNO). The only input to the RN modeling approach is the DW inclination angle distribution, as measured previously with respect to the polar c-axis. The simulations then show that a 2D network of Ohmic resistors not only adequately accounts for the different boundary conditions envisaged in experiments, but equally well provides a direct link between the local domain wall conductivity (DWC) and the DW inclination angle α. Moreover, the RN simulations can be directly compared to local-scale transport measurements, as obtained by scanning probe techniques. The conceptual simplicity and the low computational e...

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Coupled Current Jumps and Domain Wall Creeps in a Defect‐Engineered Ferroelectric Resistive Memory

Huang

Xie

Feng

et al. 2021

Adv Elect Materials

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Ferroelectric (FE) resistive switching has attracted considerable interest as a promising candidate for applications in non‐volatile memory technology. In this work, via judiciously controlling the defect states of oxygen vacancy through Sm‐doping, the authors obtain multiple current jumps/discrete resistance states in the resistive switching memories based on a model FE BiFeO3 (BFO). These hitherto unreported current jumps are attributed to the space‐charge‐limited current correlated with electron trapping by oxygen vacancies in the BFO film. Concurrently, oxygen vacancies serve as the pinning centers for the FE domains, leading to the domain wall creep behavior. These results illustrate the strong interplay between the defect, resistive switching, and domain wall creep behavior in FE diodes, providing a new insight into the mechanism of FE resistive switching. Overall, the large on/off ratio of ≈5 × 105, multiple resistance states, and fast switching speed of ≈30 ns, promise their potential applications in multi‐level data storage memories.

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Quantum properties of charged ferroelectric domain walls

Cited by 24 publications

References 37 publications

Physics and applications of charged domain walls

Physics and applications of charged domain walls

Resistor Network Modeling of Conductive Domain Walls in Lithium Niobate

Coupled Current Jumps and Domain Wall Creeps in a Defect‐Engineered Ferroelectric Resistive Memory

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