Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

Li, Wei; Ma, Yunpeng; Feng, Tianyi; Du, Ziwan; Liu, Yixuan; Kalinin, Sergei V.; Li, Jing‐Feng; Li, Qian

doi:10.1016/j.jmat.2022.09.011

Cited by 20 publications

(22 citation statements)

References 42 publications

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“…The large I [100] / I [‐110] ratio and spatial variations of the SHG intensity at the apex suggest the formation of structural inhomogeneities during the early growth stage, inducing in‐plane lattice strains that perturb a perfectly symmetrical six‐fold pattern of the SHG anisotropy. [ 33 ] These strains appear to be released and then somewhat reversed during the following growth (solidification) stages, suggesting a correlated segregation of certain chemical species along the vertical direction. Both P and Se have large volatility at the growth temperatures and thus are most likely the cause (in some poor growth cases, glassy P x Se y is often found to form at the top end).…”

Section: Resultsmentioning

confidence: 99%

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Lai

Bai

et al. 2023

Advanced Materials

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Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, high‐quality centimeter‐sized LiInP2Se6 single crystals are developed using the Bridgman method and their structure and property characteristics are systematically investigated. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α‐particles generated from an 241Am source and robust, well‐defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/γ‐ray irradiation. The primary mechanisms of Se‐vacancy and InLi antisite defects in the carrier trapping process are also identified. Such insights are critical for further enhancing the energy resolution of LiInP2Se6 bulk crystals toward the intrinsic level (≈8.6% as indicated by the chemical vapor transport‐grown thin crystals). These results pave the way for practically adopting LiInP2Se6 single crystals in new‐generation solid‐state neutron detectors.

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Section: Resultsmentioning

confidence: 99%

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Lai

Bai

et al. 2023

Advanced Materials

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“…SHG is widely used to determine the symmetry and the ferroelectricity of lowdimensional ferroelectrics. [14] Three KNN samples show the oscilloscope traces of the SHG signals at 532 nm (Figure 2g and Figure S2, Supporting Information), suggesting the presence of ferroelectricity. [15] Interestingly, the pole figure of SHG shows a clear fourfold symmetry in the KNN-3 sample (the inset of Figure 2g), which is inapparent in KNN-1 and KNN-2 samples (Figure S2, Supporting Information), indicating its more anisotropic lattice structure.…”

Section: Structure Characterizationmentioning

confidence: 99%

Lead‐Free (K, Na)NbO₃ Piezocatalyst with Superior Piezocatalysis and Large‐Scale Production

Wang,

Liao

et al. 2023

Adv Funct Materials

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Although piezocatalysis has achieved preliminary achievements in environmental remediation and biomedical applications, large‐scale fabrication of piezocatalysts with high degradation efficiency and low cost remains challenging. In this work, a new and easy strategy to solve this challenge is innovatively proposed, that is, ceramic‐powder‐driven boosted polarization intensity, and validated the strategy is by examining potassium sodium niobate ((K, Na)NbO3, KNN) ferroelectric. KNN‐3 piezocatalyst, obtained by grinding as‐sintered ceramics into powder, shows a degradation rate (k) as high as 148 × 10−3 min−1 for rhodamine B (RhB) dye and for 31 × 10−3 min−1 for methyl orange (MO) dye, ≈18 times and 66 times than those of previously reported KNN piezocatalysts. The superior piezocatalytic activity is attributed to enhanced polarization intensity, increased oxygen vacancies, and higher charge carrier concentrations. Besides, the KNN‐3 piezocatalyst shows excellent inhibitory effects on Staphylococcus aureus and Escherichia coli strains. Therefore, the proven ceramic preparation technology enables the new strategy to mass produce high‐performance KNN piezocatalysts that hold promise for applications in dye degradation and biomedicine.

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“…SHG microscopy has proven its efficiency in analyzing polarization states and symmetry aspects in various systems [31][32][33] among which: thermotropic phase boundaries, [34] phase coexistence in thin films [35] and heterostructures, [36] phase transitions, [37,38] non-Ising and chiral ferroelectric domain walls, [39,40] as well as polar domain boundaries in centrosymmetric materials. [41] The variation of the SHG polarization with the light polarization provides a unique way to probe the nonlinear optical susceptibility tensor, and with this, to gain information on the local structure, symmetry, and polarization orientation in ferroelectric materials.…”

Section: Revealing Polar Nanodomains By Means Of Second-harmonic Micr...mentioning

confidence: 99%

Automatic Ferroelectric Domain Pattern Recognition Based on the Analysis of Localized Nonlinear Optical Responses Assisted by Machine Learning

Croes

Gaponenko

Voulot

et al. 2022

Advanced Physics Research

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Second-harmonic generation (SHG) is a nonlinear optical method allowing the study of the local structure, symmetry, and ferroic order in noncentrosymmetric materials such as ferroelectrics. The combination of SHG microscopy with local polarization analysis is particularly efficient for deriving the local polarization orientation. This, however, entails the use of tedious and time-consuming modeling methods of nonlinear optical emission. Moreover, extracting the complex domain structures often observed in thin films requires a pixel-by-pixel analysis and the fitting of numerous polar plots to ascribe a polarization angle to each pixel. Here, the domain structure of GeTe films is studied using SHG polarimetry assisted by machine learning. The method is applied to two film thicknesses: A thick film containing large domains visible in SHG images, and a thin film in which the domains' size is below the SHG resolution limit. Machine learning-assisted methods show that both samples exhibit four domain variants of the same type. This result is confirmed in the case of the thick film, both by the manual pixel-by-pixel analysis and by using piezoresponse force microscopy. The proposed approach foreshows new prospects for optical studies by enabling enhanced sensitivity and high throughput analysis.

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Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

Cited by 20 publications

References 42 publications

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Lead‐Free (K, Na)NbO₃ Piezocatalyst with Superior Piezocatalysis and Large‐Scale Production

Automatic Ferroelectric Domain Pattern Recognition Based on the Analysis of Localized Nonlinear Optical Responses Assisted by Machine Learning

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Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

Cited by 20 publications

References 42 publications

Robust Thermal Neutron Detection by LiInP2Se6 Bulk Single Crystals

Robust Thermal Neutron Detection by LiInP2Se6 Bulk Single Crystals

Lead‐Free (K, Na)NbO3 Piezocatalyst with Superior Piezocatalysis and Large‐Scale Production

Automatic Ferroelectric Domain Pattern Recognition Based on the Analysis of Localized Nonlinear Optical Responses Assisted by Machine Learning

Contact Info

Product

Resources

About

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Robust Thermal Neutron Detection by LiInP₂Se₆ Bulk Single Crystals

Lead‐Free (K, Na)NbO₃ Piezocatalyst with Superior Piezocatalysis and Large‐Scale Production