scholarly journals Phase Transition Effect on Ferroelectric Domain Surface Charge Dynamics in BaTiO3 Single Crystal

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4463
Author(s):  
Dongyu He ◽  
Xiujian Tang ◽  
Yuxin Liu ◽  
Jian Liu ◽  
Wenbo Du ◽  
...  
Keyword(s):  
Phase Transition ◽  
Domain Wall ◽  
Single Crystal ◽  
Surface Charge ◽  
Potential Barrier ◽  
Surface Potential ◽  
Topological Defects ◽  
Ferroelectric Domain ◽  
Charge Dynamics ◽  
Surrounding Environment

The ferroelectric domain surface charge dynamics after a cubic-to-tetragonal phase transition on the BaTiO3 single crystal (001) surface was directly measured through scanning probe microscopy. The captured surface potential distribution shows significant changes: the domain structures formed rapidly, but the surface potential on polarized c domain was unstable and reversed its sign after lengthy lapse; the high broad potential barrier burst at the corrugated a-c domain wall and continued to dissipate thereafter. The generation of polarization charges and the migration of surface screening charges in the surrounding environment take the main responsibility in the experiment. Furthermore, the a-c domain wall suffers large topological defects and polarity variation, resulting in domain wall broadening and stress changes. Thus, the a-c domain wall has excess energy and polarization change is inclined to assemble on it. The potential barrier decay with time after exposing to the surrounding environment also gave proof of the surface screening charge migration at surface. Thus, both domain and domain wall characteristics should be taken into account in ferroelectric application.

scholarly journals Interactions of Na+ Cations with a Highly Charged Fatty Acid Langmuir Monolayer: Molecular Description of the Phase Transition

2019 ◽  
Author(s):  
Adrien Sthoer ◽  
Eric Tyrode
Keyword(s):  
Phase Transition ◽  
Surface Charge ◽  
Surface Potential ◽  
Arachidic Acid ◽  
Ion Pairs ◽  
Theoretical Models ◽  
Langmuir Monolayer ◽  
Vibrational Sum Frequency Spectroscopy ◽  
Ion Size ◽  
Contact Ion Pairs

Vibrational sum frequency spectroscopy has been used to study the molecular properties upon compression of a highly charged arachidic acid Langmuir monolayer, which displays a first order phase transition plateau in the surface pressure - molecular area (p-A) isotherm. By targeting vibrational modes from the carboxylic acid headgroup, alkyl chain, and interfacial water molecules, information regarding the surface charge, surface potential, type of ion pair formed, and conformational order of the monolayer could be extracted. The monolayer in the liquid expanded phase is found to be fully charged until reaching the 2D-phase transition plateau, where partial reprotonation, as well as the formation of COO⎺ Na<sup>+ </sup>contact-ion pairs, start to take place. In the condensed phase after the transition, three headgroup species, mainly hydrated COO⎺, COOH, and COO⎺ Na<sup>+ </sup>contact-ion pairs could be identified and their proportions quantified. Comparison with theoretical models shows that despite the low ionic strengths used (i.e. 10 mM), the predictions from the Gouy Chapman model are only adequate for the lowest surface densities, when the surface charge does not exceed -0.1 C/m<sup>2</sup>. In contrast, a modified Poisson-Boltzmann (MPB) model that accounts for the steric effects associated with the finite ion-size, captures many of the experimental observables, including the partial reprotonation, and surface potential changes upon compression. The agreement highlights the importance of hydronium ion – carboxylate interactions, as well as the layer of sodium ions packed at the steric limit, for explaining the phase transition behavior. The MPB model, however, does not explicitly consider the formation of contact ion pairs with the sodium counterion. The experimental results provide a quantitative molecular insight that could be used to test potential extensions to the theory.

Surface Charge Imaging in Semiconductor Wafers by Surface Photovoltage (SPV)

1992 ◽  
Vol 261 ◽  
Author(s):  
Piotr Edelman ◽  
Jacek Lagowski ◽  
Lubek Jastrzebski
Keyword(s):  
Surface Charge ◽  
Potential Barrier ◽  
Surface Potential ◽  
Surface Photovoltage ◽  
High Excitation ◽  
Wafer Scale ◽  
Contact Measurement

ABSTRACTWe present fast, wafer-scale imaging of the surface charge achieved via non-contact measurement of the surface potential barrier by surface photovoltage (SPV) under high excitation levels. The approach is capable of resolving surface charge differences as small as 108 q/cm2. Fundamentals of surface charge imaging are discussed, and the method is compared with standard SPV contamination mapping. Examples include problems relevant to silicon IC fabrication and surface charge maps of GaAs and InP.

scholarly journals Ferroelectric Domain Wall Motion in Freestanding Single‐Crystal Complex Oxide Thin Film

2019 ◽  
Vol 32 (4) ◽  
pp. 1907036 ◽  
Author(s):  
Saidur R. Bakaul ◽  
Jaegyu Kim ◽  
Seungbum Hong ◽  
Mathew J. Cherukara ◽  
Tao Zhou ◽  
...  
Keyword(s):  
Thin Film ◽  
Domain Wall ◽  
Single Crystal ◽  
Wall Motion ◽  
Domain Wall Motion ◽  
Complex Oxide ◽  
Ferroelectric Domain ◽  
Oxide Thin Film ◽  
Crystal Complex

Optical birefringence imaging of the phase transition of K2Mn2(SO4)3

2003 ◽  
Vol 36 (3) ◽  
pp. 914-919 ◽  
Author(s):  
C. Hernández-Rodríguez ◽  
M. A. Geday ◽  
J. Kreisel ◽  
A. M. Glazer ◽  
A. Hidalgo-López
Keyword(s):  
Phase Transition ◽  
Domain Wall ◽  
Single Crystal ◽  
Optical Anisotropy ◽  
Optical Indicatrix ◽  
Optical Birefringence ◽  
Temperature Changes ◽  
Moving Images ◽  
Two Phases ◽  
Type Crystal

The present paper reports on the observation of the optical birefringence as a function of temperature of the langbeinite-type crystal K2Mn2(SO4)3by using an imaging version of the so-called rotating-polarizer method. This method provides separate moving images of the orientation of the optical indicatrix and the magnitude of the optical anisotropy, showing the domain-wall behaviour during temperature changes. Some new results on the domain behaviour of the phase transition of K2Mn2(SO4)3have been obtained. It is concluded that the sample single crystal consists of local regions, indicating the coexistence of two phases in this langbeinite-type crystal.

Phase transition induced recrystallization and low surface potential barrier leading to 10.91%-efficient CsPbBr3 perovskite solar cells

Nano Energy ◽  
2019 ◽  
Vol 65 ◽  
pp. 104015 ◽  
Author(s):  
Guoqing Tong ◽  
Taotao Chen ◽  
Huan Li ◽  
Longbin Qiu ◽  
Zonghao Liu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solar Cells ◽  
Potential Barrier ◽  
Surface Potential ◽  
Perovskite Solar Cells

scholarly journals Interactions of Na+ Cations with a Highly Charged Fatty Acid Langmuir Monolayer: Molecular Description of the Phase Transition

2019 ◽  
Author(s):  
Adrien Sthoer ◽  
Eric Tyrode
Keyword(s):  
Phase Transition ◽  
Surface Charge ◽  
Surface Potential ◽  
Arachidic Acid ◽  
Ion Pairs ◽  
Theoretical Models ◽  
Langmuir Monolayer ◽  
Vibrational Sum Frequency Spectroscopy ◽  
Ion Size ◽  
Contact Ion Pairs

Vibrational sum frequency spectroscopy has been used to study the molecular properties upon compression of a highly charged arachidic acid Langmuir monolayer, which displays a first order phase transition plateau in the surface pressure - molecular area (p-A) isotherm. By targeting vibrational modes from the carboxylic acid headgroup, alkyl chain, and interfacial water molecules, information regarding the surface charge, surface potential, type of ion pair formed, and conformational order of the monolayer could be extracted. The monolayer in the liquid expanded phase is found to be fully charged until reaching the 2D-phase transition plateau, where partial reprotonation, as well as the formation of COO⎺ Na<sup>+ </sup>contact-ion pairs, start to take place. In the condensed phase after the transition, three headgroup species, mainly hydrated COO⎺, COOH, and COO⎺ Na<sup>+ </sup>contact-ion pairs could be identified and their proportions quantified. Comparison with theoretical models shows that despite the low ionic strengths used (i.e. 10 mM), the predictions from the Gouy Chapman model are only adequate for the lowest surface densities, when the surface charge does not exceed -0.1 C/m<sup>2</sup>. In contrast, a modified Poisson-Boltzmann (MPB) model that accounts for the steric effects associated with the finite ion-size, captures many of the experimental observables, including the partial reprotonation, and surface potential changes upon compression. The agreement highlights the importance of hydronium ion – carboxylate interactions, as well as the layer of sodium ions packed at the steric limit, for explaining the phase transition behavior. The MPB model, however, does not explicitly consider the formation of contact ion pairs with the sodium counterion. The experimental results provide a quantitative molecular insight that could be used to test potential extensions to the theory.

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