Polarization-dependent local conductivity and activation energy in KTiOPO4

Lindgren, Gustav; Kalinin, Sergei V.; Vasudevan, Rama K.; Canalias, Carlota

doi:10.1063/1.5090475

Cited by 3 publications

(3 citation statements)

References 17 publications

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“…Correspondingly, an Arrhenius plot (Figure 4d), derived from the BEPS amplitudes at +10 V, reveals an activation energy of 0.10 eV for both environments. [35,36] While 0.10 eV is lower than typical activation energies associated with bulk oxygen vacancy dynamics, it has been shown the large electric fields associated with PFM (>1 MV cm −1 ) can significantly lower the defect energy of formation, and potentially diffusion barriers. [37][38][39] Additionally, examination of the IV curves (Figure 4e) reveals an onset voltage of ≈−2.5 V for all temperatures.…”

Section: Resultsmentioning

confidence: 99%

Oxygen Vacancy Injection as a Pathway to Enhancing Electromechanical Response in Ferroelectrics

et al. 2021

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Since their discovery in late 1940s, perovskite ferroelectric materials have become one of the central objects of condensed matter physics and materials science due to the broad spectrum of functional behaviors they exhibit, including electro‐optical phenomena and strong electromechanical coupling. In such disordered materials, the static properties of defects such as oxygen vacancies are well explored but the dynamic effects are less understood. In this work, the first observation of enhanced electromechanical response in BaTiO3 thin films is reported driven via dynamic local oxygen vacancy control in piezoresponse force microscopy (PFM). A persistence in peizoelectricity past the bulk Curie temperature and an enhanced electromechanical response due to a created internal electric field that further enhances the intrinsic electrostriction are explicitly demonstrated. The findings are supported by a series of temperature dependent band excitation PFM in ultrahigh vacuum and a combination of modeling techniques including finite element modeling, reactive force field, and density functional theory. This study shows the pivotal role that dynamics of vacancies in complex oxides can play in determining functional properties and thus provides a new route toward– achieving enhanced ferroic response with higher functional temperature windows in ferroelectrics and other ferroic materials.

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Section: Resultsmentioning

confidence: 99%

Oxygen Vacancy Injection as a Pathway to Enhancing Electromechanical Response in Ferroelectrics

et al. 2021

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“…The growing interest to the local KTP studies by various SPM techniques has been stimulated by the demonstration of the increased conductivity of the domain walls , and coupling between bulk ionic transport and ferroelectricity . The switching spectroscopy PFM analysis has been applied to map the distribution of hysteresis loop parameters over the periodically poled KTP sample; however, the shape of the growing domains has not been analyzed.…”

Section: Introductionmentioning

confidence: 99%

Influence of Humidity on Local Polarization Reversal in a Rb:KTP Single Crystal

Шишкина

Пелегова

Kosobokov

et al. 2020

ACS Appl. Electron. Mater.

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The influence of the relative humidity on the domain growth during local switching by a conductive tip of a scanning probe microscope has been studied in Rb:KTP single crystals. The abnormal formation of the elongated hexagonal domains during the local switching in an axial-symmetric field has been attributed to the anisotropy of the domain wall velocity. The increase and subsequent decrease in a hexagonal domain aspect ratio as a function of the pulse duration for high humidity have been attributed to the influence of the high-resistivity water layer. We assume that the domain elongation by the fast walls is limited by the water layer representing the series resistance, which depends on the wall position, while the domain widening by the slow walls is limited by their mobility. The computer simulation of the spatial distribution of the electric field has demonstrated that the appearance of a water meniscus decreases the field close to the tip and increases it far from the tip. This result has allowed explaining the published alternative effects of humidity on the domain size: (1) decrease in size for small domains and (2) increase in size for large ones. The obtained results highlight the necessity of humidity control for domain engineering.

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“…In contrast to the insulating bulk, domain walls in ferroelectrics can be very good electrical conductors [7][8][9][10][11][12][13][14][15][16][17][18] (even superconductors 19 ). In many cases, conductivity depends on the local divergence of the polarization (or magnitude of the polar discontinuity perpendicular to the wall).…”

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confidence: 99%

Conducting ferroelectric domain walls emulating aspects of neurological behavior

Suna

Baxter

McConville

et al. 2022

Applied Physics Letters

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The electrical conductivity of lithium niobate thin film capacitor structures depends on the density of conducting 180[Formula: see text] domain walls, which traverse the interelectrode gap, and on their inclination angle with respect to the polarization axis. Both microstructural characteristics can be altered by applying electric fields, but changes are time-dependent and relax, upon field removal, into a diverse range of remanent states. As a result, the measured conductance is a complex history-dependent function of electric field and time. Here, we show that complexity in the kinetics of microstructural change, in this ferroelectric system, can generate transport behavior that is strongly reminiscent of that seen in key neurological building blocks, such as synapses. Successive voltage pulses, of positive and negative polarity, progressively enhance or suppress domain wall related conductance (analogous to synaptic potentiation and depression), in a way that depends on both the pulse voltage magnitude and frequency. Synaptic spike-rate-dependent plasticity and even Ebbinghaus forgetting behavior, characteristic of learning and memory in the brain, can be emulated as a result. Conductance can also be changed according to the time difference between designed identical voltage pulse waveforms, applied to top and bottom contact electrodes, in a way that can mimic both Hebbian and anti-Hebbian spike-timing-dependent plasticity in synapses. While such features have been seen in, and developed for, other kinds of memristors, few have previously been realized through the manipulation of conducting ferroelectric domain walls.

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Polarization-dependent local conductivity and activation energy in KTiOPO4

Cited by 3 publications

References 17 publications

Oxygen Vacancy Injection as a Pathway to Enhancing Electromechanical Response in Ferroelectrics

Oxygen Vacancy Injection as a Pathway to Enhancing Electromechanical Response in Ferroelectrics

Influence of Humidity on Local Polarization Reversal in a Rb:KTP Single Crystal

Conducting ferroelectric domain walls emulating aspects of neurological behavior

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