Control of polarization in bulk ferroelectrics by mechanical dislocation imprint

Science ◽  
2021 ◽  
Vol 372 (6545) ◽  
pp. 961-964
Author(s):  
Marion Höfling ◽  
Xiandong Zhou ◽  
Lukas M. Riemer ◽  
Enrico Bruder ◽  
Binzhi Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Point Defects ◽  
Piezoelectric Coefficient ◽  
Local Level ◽  
Functional Materials ◽  
Pinning Force ◽  
Large Signal ◽  
Restoring Force ◽  
Field Dependent

Defects are essential to engineering the properties of functional materials ranging from semiconductors and superconductors to ferroics. Whereas point defects have been widely exploited, dislocations are commonly viewed as problematic for functional materials and not as a microstructural tool. We developed a method for mechanically imprinting dislocation networks that favorably skew the domain structure in bulk ferroelectrics and thereby tame the large switching polarization and make it available for functional harvesting. The resulting microstructure yields a strong mechanical restoring force to revert electric field–induced domain wall displacement on the macroscopic level and high pinning force on the local level. This induces a giant increase of the dielectric and electromechanical response at intermediate electric fields in barium titanate [electric field–dependent permittivity (ε33) ≈ 5800 and large-signal piezoelectric coefficient (d33*) ≈ 1890 picometers/volt]. Dislocation-based anisotropy delivers a different suite of tools with which to tailor functional materials.

scholarly journals Low- and high-field electromechanical responses of relaxor-based multicomponent ceramics for application in multiregime actuators

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060004
Author(s):  
M. V. Talanov ◽  
A. A. Pavelko ◽  
L. A. Reznichenko
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Solid Solutions ◽  
High Field ◽  
Piezoelectric Coefficient ◽  
Large Signal ◽  
Electromechanical Responses ◽  
High Electric Fields

The electromechanical responses of multicomponent solid solutions [Formula: see text][Formula: see text]([Formula: see text][Formula: see text])[Formula: see text]([Formula: see text][Formula: see text])[Formula: see text]([Formula: see text][Formula: see text])[Formula: see text][Formula: see text]O3 in low and high electric fields were studied. In both cases, significant electromechanical responses are observed. In particular, the maximum values of the large-signal piezoelectric coefficient [Formula: see text] reach 1600[Formula: see text]m/V at very low values of the electric field ([Formula: see text]5[Formula: see text]kV/cm). The observed features of the electromechanical responses of the studied ceramics are advantages in terms of their possible application in actuators.

scholarly journals Quantification of pulsed electric field for the rupture of giant vesicles with various surface charges, cholesterols and osmotic pressures

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262555
Author(s):  
Md. Kabir Ahamed ◽  
Marzuk Ahmed ◽  
Mohammad Abu Sayem Karal
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Mole Fraction ◽  
High Frequency ◽  
Pulsed Electric Field ◽  
Surface Charges ◽  
Maximum Probability ◽  
Giant Vesicles ◽  
Biochemical Processes ◽  
Field Dependent

Electropermeabilization is a promising phenomenon that occurs when pulsed electric field with high frequency is applied to cells/vesicles. We quantify the required values of pulsed electric fields for the rupture of cell-sized giant unilamellar vesicles (GUVs) which are prepared under various surface charges, cholesterol contents and osmotic pressures. The probability of rupture and the average time of rupture are evaluated under these conditions. The electric field changes from 500 to 410 Vcm-1 by varying the anionic lipid mole fraction from 0 to 0.60 for getting the maximum probability of rupture (i.e., 1.0). In contrast, the same probability of rupture is obtained for changing the electric field from 410 to 630 Vcm-1 by varying the cholesterol mole fraction in the membranes from 0 to 0.40. These results suggest that the required electric field for the rupture decreases with the increase of surface charge density but increases with the increase of cholesterol. We also quantify the electric field for the rupture of GUVs containing anionic mole fraction of 0.40 under various osmotic pressures. In the absence of osmotic pressure, the electric field for the rupture is obtained 430 Vcm-1, whereas the field is 300 Vcm-1 in the presence of 17 mOsmL-1, indicating the instability of GUVs at higher osmotic pressures. These investigations open an avenue of possibilities for finding the electric field dependent rupture of cell-like vesicles along with the insight of biophysical and biochemical processes.

scholarly journals Neutron diffraction on functional materials under electric field or mech. load

2014 ◽  
Vol 70 (a1) ◽  
pp. C56-C56
Author(s):  
Markus Hoelzel ◽  
Manuel Hinterstein ◽  
Peter Kadletz ◽  
Wolfgang Schmahl
Keyword(s):  
Neutron Diffraction ◽  
Electric Field ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electric Fields ◽  
Elastic Constants ◽  
Mechanical Load ◽  
Functional Materials ◽  
Ferroelectric Ceramics ◽  
High Electric Fields

In this contribution neutron diffraction studies on functional materials under special environmenal conditions will be presented. In particular, studies of ferroelectric ceramics under high electric fields as well as shape memory alloys under mechanical load will be highlighted. The investigations were carried out at the high-resolution neutron powder diffractometer SPODI (FRM II / Garching n. Munich) which offers special sample environmenal tools for electric fields, mechanical load etc. In-situ studies on ferroelectrics under the influence of high electric fields enable to establish correlations between the macroscopic poling behaviour and corresponding structural changes. The investigations were carried out on technologically applied lead zirconate titanate based samples and on a bismuth sodium titanate based system. A self-designed device allows the investigation of large bulk samples under different orientations of the electric field. This method allows to analyze the poling mechanisms in technical ferroelectrics, such as piezoelectric effect, domain reorientation and phase transformations. In the system Bi0.5Na0.5TiO3 - BaTiO3 – K0.5Na0.5NbO3 the large recoverable field-induced strain could be attributed to a reversible field-induced phase transition from an almost non-polar, pseudocubic tetragonal phase to a distorted, ferroelectric active phase [1]. Polycristalline monoclinic nickel-titanium shape memory alloys have been investigated under mechanical load to analyze their stress-strain behaviour and to derive the elastic constants. A novel tensile rig allows to orient the load axis in a Eulerian cradle like manner. The elastic constants tensor could be calculated based on a series of diffraction patterns under different sample orientations in the initial state and under 0.6 % strain. Furthermore the contributions of elastic deformation (lattice dilatation) and inelastic deformation (orentation of twins) to the total strain could be separated.

BLOCH DYNAMICS IN SPATIALLY LOCAL INHOMOGENEOUS ELECTRIC FIELDS

2001 ◽  
Vol 11 (02) ◽  
pp. 425-453
Author(s):  
JOSEPH P. REYNOLDS ◽  
GERALD J. IAFRATE ◽  
JUN HE
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Nearest Neighbor ◽  
Constant Electric Field ◽  
Tight Binding ◽  
Homogeneous Field ◽  
Wannier Functions ◽  
Field Dependent ◽  
Bloch Electrons ◽  
Special Case

The influence of local inhomogeneities on the electric field dependent properties of Bloch electrons is studied. The homogeneous electric field is described through the use of the vector potential, and the instantaneous Wannier functions of the homogeneous field dependent Hamiltonian are used as bases states to depict Bloch dynamics and properties. Model examples are treated using Slater-Koster inhomogeneities and nearest-neighbor tight-binding band structure in a one dimensional, single-band analysis. Detailed analysis is presented for the special case of a constant electric field; here the influence of localization due to the presence of the electric field is shown to clearly affect the energy spectrum of the Bloch electron for a single and double impurity configuration.

scholarly journals Nanoscale electric-field imaging based on a quantum sensor and its charge-state control under ambient condition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ke Bian ◽  
Wentian Zheng ◽  
Xianzhe Zeng ◽  
Xiakun Chen ◽  
Rainer Stöhr ◽  
...  
Keyword(s):  
Electric Field ◽  
Charge State ◽  
Electric Fields ◽  
Functional Materials ◽  
Electric Polarization ◽  
Nitrogen Vacancy ◽  
State Control ◽  
Atomic Force ◽  
The Magnetic Field ◽  
Field Imaging

AbstractNitrogen-vacancy (NV) centers in diamond can be used as quantum sensors to image the magnetic field with nanoscale resolution. However, nanoscale electric-field mapping has not been achieved so far because of the relatively weak coupling strength between NV and electric field. Here, using individual shallow NVs, we quantitatively image electric field contours from a sharp tip of a qPlus-based atomic force microscope (AFM), and achieve a spatial resolution of ~10 nm. Through such local electric fields, we demonstrated electric control of NV’s charge state with sub-5 nm precision. This work represents the first step towards nanoscale scanning electrometry based on a single quantum sensor and may open up the possibility of quantitatively mapping local charge, electric polarization, and dielectric response in a broad spectrum of functional materials at nanoscale.

scholarly journals Maxwell Equations Without a Polarization Field, Using a Paradigm from Biophysics

2020 ◽  
Author(s):  
Robert Eisenberg
Keyword(s):  
Integrated Circuits ◽  
Electric Field ◽  
Electric Fields ◽  
Operational Definition ◽  
Polarization Field ◽  
Charge Movement ◽  
Electrical Measurements ◽  
Field Dependent ◽  
Dependent Polarization ◽  
Electrodynamic Forces

Electrodynamics is usually written using polarization fields to describe changes in distribution of charge as electric fields change. This approach does not specify polarization fields uniquely from electrical measurements. Many polarization fields will produce the same electrodynamic forces and flows because only divergence of polarization enters Maxwell’s first equation, relating charge and electric field. The curl of any function can be added to a polarization field without changing the electric field at all. The divergence of the curl is always zero. To be unique, models must describe the charge distribution and how it varies. I propose a different paradigm to describe field dependent charge, i.e., the phenomenon of polarization. This operational definition of polarization has worked well in biophysics for fifty years, where a field dependent, time dependent polarization provides gating current that makes neurons respond sensitively to voltage. Theoretical estimates of polarization computed with this definition fit experimental data. I propose that operational definition be used to define polarization charge in general. Charge movement needs to be computed from a combination of electrodynamics and mechanics because ‘everything interacts with everything else’. The classical polarization field need not enter into that treatment at all. When nothing is known about polarization, it is necessary to use an approximate representation with a dielectric constant that is a single real positive number. This approximation allows important results in some cases, e.g., design of integrated circuits in silicon semiconductors, but can be seriously misleading in other cases, e.g., ionic solutions.

Electroreflectance and Photoreflectance Studies of Electric Fields in Pt/GaN Schottky Diodes and AlGaN/GaN Heterostructures

2002 ◽  
Vol 743 ◽  
Author(s):  
S. Shokhovets ◽  
R. Goldhahn ◽  
G. Gobsch ◽  
O. Ambacher ◽  
I. P. Smorchkova ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Electric Fields ◽  
Schottky Diodes ◽  
Schottky Contact ◽  
Surface Charges ◽  
Temperature Dependent ◽  
Algan Barrier ◽  
Field Dependent ◽  
Increasing Temperature

ABSTRACTWe have performed electroreflectance and photoreflectance studies of Pt/GaN Schottky diodes with Ga- and N-face polarity as well as AlGaN/GaN based transistor heterostructures. The experimental data were analyzed using electric field-dependent dielectric functions of GaN and AlGaN. Inhomogeneities in the electric fields were taken into account by application of a multi-layer formalism. We observed an increase of the electric field strength underneath the Schottky contact and in the AlGaN barrier with increasing temperature. The results are explained in terms of temperature dependent densities of ionized impurities and surface charges.

scholarly journals Maxwell Equations Without a Polarization Field, Using a Paradigm from Biophysics

2020 ◽  
Author(s):  
Robert Eisenberg
Keyword(s):  
Integrated Circuits ◽  
Electric Field ◽  
Electric Fields ◽  
Operational Definition ◽  
Polarization Field ◽  
Charge Movement ◽  
Electrical Measurements ◽  
Field Dependent ◽  
Dependent Polarization ◽  
Electrodynamic Forces

Electrodynamics is usually written using polarization fields to describe changes in distribution of charge as electric fields change. This approach does not specify polarization fields uniquely from electrical measurements. Many polarization fields will produce the same electrodynamic forces and flows because only divergence of polarization enters Maxwell’s first equation, relating charge and electric field. The curl of any function can be added to a polarization field without changing the electric field at all. The divergence of the curl is always zero. To be unique, models must describe the charge distribution and how it varies. I propose a different paradigm to describe field dependent charge, i.e., the phenomenon of polarization. This operational definition of polarization has worked well in biophysics for fifty years, where a field dependent, time dependent polarization provides gating current that makes neurons respond sensitively to voltage. Theoretical estimates of polarization computed with this definition fit experimental data. I propose that operational definition be used to define polarization charge in general. Charge movement needs to be computed from a combination of electrodynamics and mechanics because ‘everything interacts with everything else’. The classical polarization field need not enter into that treatment at all. When nothing is known about polarization, it is necessary to use an approximate representation with a dielectric constant that is a single real positive number. This approximation allows important results in some cases, e.g., design of integrated circuits in silicon semiconductors, but can be seriously misleading in other cases, e.g., ionic solutions.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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