The increasing miniaturization of electronics requires a better understanding of material properties at the nanoscale. Many studies have shown that there is a ferroelectric size limit in oxides, below which the ferroelectricity will be strongly suppressed due to the depolarization field, and whether such a limit still exists in the absence of the depolarization field remains unclear. Here, by applying uniaxial strain, we obtain pure in-plane polarized ferroelectricity in ultrathin SrTiO_{3} membranes, providing a clean system with high tunability to explore ferroelectric size effects especially the thickness-dependent ferroelectric instability with no depolarization field. Surprisingly, the domain size, ferroelectric transition temperature, and critical strain for room-temperature ferroelectricity all exhibit significant thickness dependence. These results indicate that the stability of ferroelectricity is suppressed (enhanced) by increasing the surface or bulk ratio (strain), which can be explained by considering the thickness-dependent dipole-dipole interactions within the transverse Ising model. Our study provides new insights into ferroelectric size effects and sheds light on the applications of ferroelectric thin films in nanoelectronics.
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http://dx.doi.org/10.1103/PhysRevLett.130.126801 | DOI Listing |
Nat Commun
January 2025
International Centre for Quantum Materials, Collaborative Innovation Centre of Quantum Matter, Peking University, Beijing, China.
The anomalous photovoltaic effect (APE) in polar crystals is a promising avenue for overcoming the energy conversion efficiency limits of conventional photoelectric devices utilizing p-n junction architectures. To facilitate effective photocarrier separation and enhance the APE, polar materials need to be thinned down to maximize the depolarization field. Here, we demonstrate Janus MoSSe monolayers (~0.
View Article and Find Full Text PDFHeart Rhythm
January 2025
Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA. Electronic address:
Background: Spontaneously occurring life threatening reentrant arrhythmias result when a propagating premature beat encounters a region with significant dispersion of refractoriness. Although localized structural tissue heterogeneities and prescribed cell functional gradients have been incorporated into computational electrophysiological models, a quantitative framework for the evolution from normal to abnormal behavior that occurs via disease is lacking.
Objective: The purpose of this study was to develop a probabilistic modeling framework that represents the complex interplay of cell function and tissue structure in health and disease which predicts the emergence of premature beats and the initiation of reentry.
J Phys Condens Matter
January 2025
Department of Physics, Southern University of Science and Technology, 1088 Xueyuan Rd, Xili, Nanshan District, Shenzhen, 518055, CHINA.
Miniaturization of ferroelectrics for technological applications has proven challenging due to the suppression of electric polarization caused by increasing depolarization fields as material thickness decreases. The emergence of ferroelectricity in two-dimensional (2D) van der Waals (vdW) materials offers a potential solution to this challenge, prompting significant research efforts over the past decade. While intrinsic 2D vdW ferroelectrics are scarce, polar stacking provides a more general approach to introducing ferroelectricity in these materials.
View Article and Find Full Text PDFArch Microbiol
December 2024
Centre for Research and Development of Scientific Instruments (CRDSI), Indian Institute of Technology, Jodhpur, Rajasthan, 342030, India.
Antimicrobial resistance poses a significant global health threat by reducing the effectiveness of conventional antibiotics, particularly against pathogens like Methicillin-resistant Staphylococcus aureus (MRSA). This study investigates the antimicrobial potential of rhizospheric soil bacteria from Prosopis cineraria (Sangri) in the Thar Desert. Bacterial strains isolated from these samples were observed to produce secondary metabolites, notably, Iturin A C-15 cyclic lipopeptide (SS1-3-P) which was extracted from strain Enterobacter cloacae SS1-3 and was purified and characterized using reverse-phase HPLC, ESI-LC/MS, Nile-Red Assay, and FT-IR analysis.
View Article and Find Full Text PDFCell Rep
December 2024
Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA; Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address:
A century of research established that GABA inhibits proprioceptive inputs presynaptically to sculpt spinal neural inputs into skilled motor output. Recent results in mice challenged this theory by showing that GABA can also facilitate action potential conduction in proprioceptive afferents. Here, we tackle this controversy in monkeys, the most human-relevant animal model, and show that GABA receptors (GABARs) indeed facilitate sensory inputs to spinal motoneurons and interneurons and that this mechanism also influences sensory transmission to supraspinal centers.
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