13 research outputs found
Manipulating Ferroelectrics through Changes in Surface and Interface Properties
Ferroelectric
materials are used in many applications of modern technologies including
information storage, transducers, sensors, tunable capacitors, and
other novel device concepts. In many of these applications, the ferroelectric
properties, such as switching voltages, piezoelectric constants, or
stability of nanodomains, are crucial. For any application, even for
material characterization, the material itself needs to be interfaced
with electrodes. On the basis of the structural, chemical, and electronic
properties of the interfaces, the measured material properties can
be determined by the interface. This is also true for surfaces. However,
the importance of interfaces and surfaces and their effect on experiments
are often neglected, which results in many dramatically different
experimental results for nominally identical samples. Therefore, it
is crucial to understand the role of the interface and surface properties
on internal bias fields and the domain switching process. Here, the
nanoscale ferroelectric switching process and the stability of nanodomains
for PbÂ(Zr,Ti)ÂO<sub>3</sub> thin films are investigated by using scanning
probe microscopy. Interface and surface properties are modulated through
the selection/redesign of electrode materials as well as tuning the
surface-near oxygen vacancies, which both can result in changes of
the electric fields acting across the sample, and consequently this
controls the measured ferroelectric and domain retention properties.
By understanding the role of surfaces and interfaces, ferroelectric
properties can be tuned to eliminate the problem of asymmetric domain
stability by combining the effects of different electrode materials.
This study forms an important step toward integrating ferroelectric
materials in electronic devices
Tunable Metallic Conductance in Ferroelectric Nanodomains
Metallic conductance in charged ferroelectric domain
walls was
predicted more than 40 years ago as the first example of an electronically
active homointerface in a nonconductive material. Despite decades
of research on oxide interfaces and ferroic systems, the metal–insulator
transition induced solely by polarization charges without any additional
chemical modification has consistently eluded the experimental realm.
Here we show that a localized insulator–metal transition can
be repeatedly induced within an insulating ferroelectric lead-zirconate
titanate, merely by switching its polarization at the nanoscale. This
surprising effect is traced to tilted boundaries of ferroelectric
nanodomains, that act as localized homointerfaces within the perovskite
lattice, with inherently tunable carrier density. Metallic conductance
is unique to nanodomains, while the conductivity of extended domain
walls and domain surfaces is thermally activated. Foreseeing future
applications, we demonstrate that a continuum of nonvolatile metallic
states across decades of conductance can be encoded in the size of
ferroelectric nanodomains using electric field
Atomically Resolved Electronic States and Correlated Magnetic Order at Termination Engineered Complex Oxide Heterointerfaces
We
map electronic states, band gaps, and interface-bound charges
at termination-engineered BiFeO<sub>3</sub>/La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub> interfaces using atomically resolved cross-sectional
scanning tunneling microscopy. We identify a delicate interplay of
different correlated physical effects and relate these to the ferroelectric
and magnetic interface properties tuned by engineering the atomic
layer stacking sequence at the interfaces. This study highlights the
importance of a direct atomically resolved access to electronic interface
states for understanding the intriguing interface properties in complex
oxides
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness
Mechanically Robust Interface at Metal/Muscovite Quasi van der Waals Epitaxy
Quasi van der Waals epitaxy is an approach to constructing
the
combination of 2D and 3D materials. Here, we quantify and discuss
the 2D/3D interface structure and the corresponding features in metal/muscovite
systems. High-resolution scanning transmission electron microscopy
reveals the atomic arrangement at the interface. The theoretical results
explain the formation mechanism and predict the mechanical robustness
of these metal/muscovite quasi van der Waals epitaxies. The evidence
of superior interface quality is delivered according to the outstanding
performance of the designed systems in both retention (>105 s) and cycling tests (>105 cycles) through
electromechanical
measurements. With high-temperature X-ray reciprocal space mapping,
the unique anisotropy of thermal expansion is discovered and predicted
to sustain the thermal stress with a sizable thermal actuation. A
maximum bending curvature of 264 m–1 at 243 °C
can be obtained in the silver/muscovite heteroepitaxy. The electrothermal
and photothermal methods show a fast response to thermal stress and
demonstrate the interface robustness