Unfolding the Challenges To Prepare Single Crystalline Complex Oxide Membranes by Solution Processing.

The ability to prepare single crystalline complex oxide freestanding membranes has opened a new playground to access new phases and functionalities not available when they are epitaxially bound to the substrates. The water-soluble Sr3Al2O6 (SAO) sacrificial layer approach has proven to be one of the most promising pathways to prepare a wide variety of single crystalline complex oxide membranes, typically by high vacuum deposition techniques. Here, we present solution processing, also named chemical solution deposition (CSD), as a cost-effective alternative deposition technique to prepare freestanding membranes identifying the main processing challenges and how to overcome them. In particular, we compare three different strategies based on interface and cation engineering to prepare CSD (00l)-oriented BiFeO3 (BFO) membranes. First, BFO is deposited directly on SAO but forms a nanocomposite of Sr-Al-O rich nanoparticles embedded in an epitaxial BFO matrix because the Sr-O bonds react with the solvents of the BFO precursor solution. Second, the incorporation of a pulsed laser deposited La0.7Sr0.3MnO3 (LSMO) buffer layer on SAO prior to the BFO deposition prevents the massive interface reaction and subsequent formation of a nanocomposite but migration of cations from the upper layers to SAO occurs, making the sacrificial layer insoluble in water and withholding the membrane release. Finally, in the third scenario, a combination of LSMO with a more robust sacrificial layer composition, SrCa2Al2O6 (SC2AO), offers an ideal building block to obtain (001)-oriented BFO/LSMO bilayer membranes with a high-quality interface that can be successfully transferred to both flexible and rigid host substrates. Ferroelectric fingerprints are identified in the BFO film prior and after membrane release. These results show the feasibility to use CSD as alternative deposition technique to prepare single crystalline complex oxide membranes widening the range of available phases and functionalities for next-generation electronic devices.

Aberration Correction for Large-Angle Illumination Scanning Transmission Electron Microscopy by Using Iterative Electron Ptychography Algorithms.

Modern aberration correctors in the scanning transmission electron microscope (STEM) have dramatically improved the attainable spatial resolution and enabled atomical structure and spectroscopic analysis even at low acceleration voltages (≤80 kV). For a large-angle illumination, achieving successful aberration correction to high angles is challenging with an aberration corrector, which limits further improvements in applications such as super-resolution, three-dimensional atomic depth resolution, or atomic surface morphology analyses. Electron ptychography based on four-dimensional STEM can provide a postprocessing strategy to overcome the current technological limitations. In this work, we have demonstrated that aberration correction for large-angle illumination is feasible by pushing the capabilities of regularized ptychographic iterative engine algorithms to reconstruct 4D data sets acquired using a relatively low-efficiency complementary metal oxide semiconductor camera. We report super resolution (0.71 Å) with large-angle illumination (50-60 mrad) and under 60 kV accelerating voltage.

Ultrafast Non-Volatile Floating-Gate Memory Based on All-2D Materials.

The explosive growth of massive-data storage and the demand for ultrafast data processing require innovative memory devices with exceptional performance. 2D materials and their van der Waal heterostructures with atomically sharp interfaces hold great promise for innovations in memory devices. Here, this work presents non-volatile, floating-gate memory devices with all functional layers made of 2D materials, achieving ultrafast programming/erasing speeds (20 ns), high extinction ratios (up to 108), and multi-bit storage capability. These devices also exhibit long-term data retention exceeding 10 years, facilitated by a high gate-coupling ratio (GCR) and atomically sharp interfaces between functional layers. Additionally, this work demonstrates the realization of an "OR" logic gate on a single-device unit by synergistic electrical and optical operations. The present results provide a solid foundation for next-generation ultrahigh-speed, ultralong lifespan, non-volatile memory devices, with a potential for scale-up manufacturing and flexible electronics applications.

Controlling the 2D Magnetism of CrBr3 by van der Waals Stacking Engineering.

The manipulation of two-dimensional (2D) magnetic order is of significant importance to facilitate future 2D magnets for low-power and high-speed spintronic devices. van der Waals stacking engineering makes promises for controllable magnetism via interlayer magnetic coupling. However, directly examining the stacking order changes accompanying magnetic order transitions at the atomic scale and preparing device-ready 2D magnets with controllable magnetic orders remain elusive. Here, we demonstrate the effective control of interlayer stacking in exfoliated CrBr3 via thermally assisted strain engineering. The stable interlayer ferromagnetic (FM), antiferromagnetic (AFM), and FM-AFM coexistent ground states confirmed by the magnetic circular dichroism measurements are realized. Combined with the first-principles calculations, the atomically resolved imaging technique reveals the correlation between magnetic order and interlayer stacking order in CrBr3 flakes unambiguously. A tunable exchange bias effect is obtained in the mixed phase of FM and AFM states. This work will introduce new magnetic properties by controlling the stacking order and sequence of 2D magnets, providing ample opportunities for their application in spintronic devices.

Correction to "Chemical Synthesis of La0.75Sr0.25CrO3 Thin Films for p-Type Transparent Conducting Electrodes".

[This corrects the article DOI: 10.1021/acs.chemmater.2c03831.].

A stable rhombohedral phase in ferroelectric Hf(Zr)1+xO2 capacitor with ultralow coercive field.

Hafnium oxide-based ferroelectric materials are promising candidates for next-generation nanoscale devices because of their ability to integrate into silicon electronics. However, the intrinsic high coercive field of the fluorite-structure oxide ferroelectric devices leads to incompatible operating voltage and limited endurance performance. We discovered a complementary metal-oxide semiconductor (CMOS)-compatible rhombohedral ferroelectric Hf(Zr)1+xO2 material rich in hafnium-zirconium [Hf(Zr)]. X-ray diffraction combined with scanning transmission electron microscopy reveals that the excess Hf(Zr) atoms intercalate within the hollow sites. We found that the intercalated atoms expand the lattice and increase the in-plane and out-of-plane stresses, which stabilize both the rhombohedral phase (r-phase) and its ferroelectric properties. Our ferroelectric devices, which are based on the r-phase Hf(Zr)1+xO2, exhibit an ultralow coercive field (~0.65 megavolts per centimeter). Moreover, we achieved a high endurance of more than 1012 cycles at saturation polarization. This material discovery may help to realize low-cost and long-life memory chips.

Chemical Synthesis of La0.75Sr0.25CrO3 Thin Films for p-Type Transparent Conducting Electrodes.

The imperative need for highly performant and stable p-type transparent electrodes based on abundant metals is stimulating the research on perovskite oxide thin films. Moreover, exploring the preparation of these materials with the use of cost-efficient and scalable solution-based techniques is a promising approach to extract their full potential. Herein, we present the design of a chemical route, based on metal nitrate precursors, for the preparation of pure phase La0.75Sr0.25CrO3 (LSCO) thin films to be used as a p-type transparent conductive electrode. Different solution chemistries have been evaluated to ultimately obtain dense, epitaxial, and almost relaxed LSCO films. Optical characterization of the optimized LSCO films reveals promising high transparency with ∼67% transmittance while room temperature resistivity values are 1.4 Ω·cm. It is suggested that the presence of structural defects, i.e., antiphase boundaries and misfit dislocations, affects the electrical behavior of LSCO films. Monochromated electron energy loss spectroscopy allowed changes in the electronic structure in LSCO films to be determined, revealing the creation of Cr4+ and unoccupied states at the O 2p upon Sr-doping. This work offers a new venue to prepare and further investigate cost-effective functional perovskite oxides with potential to be used as p-type transparent conducting electrodes and be easily integrated in many oxide heterostructures.

Ultrafast-Programmable 2D Homojunctions Based on van der Waals Heterostructures on a Silicon Substrate.

The development of electrically ultrafast-programmable semiconductor homojunctions can lead to transformative multifunctional electronic devices. However, silicon-based homojunctions are not programmable so that alternative materials need to be explored. Here 2D, multi-functional, lateral homojunctions made of van der Waals heterostructures with a semi-floating-gate configuration on a p++ Si substrate feature atomically sharp interfaces and can be electrostatically programmed in nanoseconds, more than seven orders of magnitude faster than other 2D-based homojunctions. By applying voltage pulses with different polarities, lateral p-n, n+ -n and other types of homojunctions can be formed, varied, and reversed. The p-n homojunctions possess a high rectification ratio of up to ≈105 and can be dynamically switched between four distinct conduction states with the current spanning over nine orders of magnitude, enabling them to function as logic rectifiers, memories, and multi-valued logic inverters. Built on a p++ Si substrate, which acts as the control gate, the devices are compatible with Si technology.

Collective Magnetic Behavior in Vanadium Telluride Induced by Self-Intercalation.

Self-intercalation of native magnetic atoms within the van der Waals (vdW) gap of layered two-dimensional (2D) materials provides a degree of freedom to manipulate magnetism in low-dimensional systems. Among various vdW magnets, the vanadium telluride is an interesting system to explore the interlayer order-disorder transition of magnetic impurities due to its flexibility in taking nonstoichiometric compositions. In this work, we combine high-resolution scanning transmission electron microscopy (STEM) analysis with density functional theory (DFT) calculations and magnetometry measurements, to unveil the local atomic structure and magnetic behavior of V-rich V1+xTe2 nanoplates with embedded V3Te4 nanoclusters grown by chemical vapor deposition (CVD). The segregation of V intercalations locally stabilizes the self-intercalated V3Te4 magnetic phase, which possesses a distorted 1T'-like monoclinic structure. This phase transition is controlled by the electron doping from the intercalant V ions. The magnetic hysteresis loops show that the nanoplates exhibit superparamagnetism, while the temperature-dependent magnetization curves evidence a collective superspin-glass magnetic behavior of the nanoclusters at low temperature. Using four-dimensional (4D) STEM diffraction imaging, we reveal the formation of collective diffuse magnetic domain structures within the sample under the high magnetic fields inside the electron microscope. Our results shed light on the studies of dilute magnetism at the 2D limit and on strategies for the manipulation of magnetism for spintronic applications.

Ferromagnetic-antiferromagnetic coexisting ground state and exchange bias effects in MnBi4Te7 and MnBi6Te10.

Natural superlattice structures MnBi2Te4(Bi2Te3)n (n = 1, 2, ...), in which magnetic MnBi2Te4 layers are separated by nonmagnetic Bi2Te3 layers, hold band topology, magnetism and reduced interlayer coupling, providing a promising platform for the realization of exotic topological quantum states. However, their magnetism in the two-dimensional limit, which is crucial for further exploration of quantum phenomena, remains elusive. Here, complex ferromagnetic-antiferromagnetic coexisting ground states that persist down to the 2-septuple layers limit are observed and comprehensively investigated in MnBi4Te7 (n = 1) and MnBi6Te10 (n = 2). The ubiquitous Mn-Bi site mixing modifies or even changes the sign of the subtle interlayer magnetic interactions, yielding a spatially inhomogeneous interlayer coupling. Further, a tunable exchange bias effect, arising from the coupling between the ferromagnetic and antiferromagnetic components in the ground state, is observed in MnBi2Te4(Bi2Te3)n (n = 1, 2), which provides design principles and material platforms for future spintronic devices. Our work highlights a new approach toward the fine-tuning of magnetism and paves the way for further study of quantum phenomena in MnBi2Te4(Bi2Te3)n (n = 1, 2) as well as their magnetic applications.

Experimental Realization of Atomic Monolayer Si9 C15.

Monolayer Six Cy constitutes an important family of 2D materials that is predicted to feature a honeycomb structure and appreciable bandgaps. However, due to its binary chemical nature and the lack of bulk polymorphs with a layered structure, the fabrication of such materials has so far been challenging. Here, the synthesis of atomic monolayer Si9 C15 on Ru (0001) and Rh(111) substrates is reported. A combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and density functional theory (DFT) calculations is used to infer that the 2D lattice of Si9 C15 is a buckled honeycomb structure. Monolayer Si9 C15 shows semiconducting behavior with a bandgap of ≈1.9 eV. Remarkably, the Si9 C15 lattice remains intact after exposure to ambient conditions, indicating good air stability. The present work expands the 2D-materials library and provides a promising platform for future studies in nanoelectronics and nanophotonics.

Bendable Polycrystalline and Magnetic CoFe2O4 Membranes by Chemical Methods.

The preparation and manipulation of crystalline yet bendable functional complex oxide membranes has been a long-standing issue for a myriad of applications, in particular, for flexible electronics. Here, we investigate the viability to prepare magnetic and crystalline CoFe2O4 (CFO) membranes by means of the Sr3Al2O6 (SAO) sacrificial layer approach using chemical deposition techniques. Meticulous chemical and structural study of the SAO surface and SAO/CFO interface properties have allowed us to identify the formation of an amorphous SAO capping layer and carbonates upon air exposure, which dictate the crystalline quality of the subsequent CFO film growth. Vacuum annealing at 800 °C of SAO films promotes the elimination of the surface carbonates and the reconstruction of the SAO surface crystallinity. Ex-situ atomic layer deposition of CFO films at 250 °C on air-exposed SAO offers the opportunity to avoid high-temperature growth while achieving polycrystalline CFO films that can be successfully transferred to a polymer support preserving the magnetic properties under bending. Float on and transfer provides an alternative route to prepare freestanding and wrinkle-free CFO membrane films. The advances and challenges presented in this work are expected to help increase the capabilities to grow different oxide compositions and heterostructures of freestanding films and their range of functional properties.

Función de la senescencia endotelial en la fisiopatología del síndrome metabólico y el envejecimiento / Role of endothelial senescence in the physiotherapy of metabolic syndrome and ageing

Estimado director: Hemos leído con interés el artículo Prevalencia del síndrome metabólico en la población dos consultorios del Policlínico Primero de Enero, de los autores Rivero Sabournin y otros.1 Dicho trabajo demuestra el potencial investigativo en la Atención Primaria de Salud, así como la pertinencia de este escenario en los estudios epidemiológicos. Para el desarrollo de la investigación sus autores se basan en los criterios de síndrome metabólico (SM) del National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III),1 aunque resulta imprescindible evaluar los criterios de la Clasificación Consensuada o Armonizada de Alberti y otros del año 2009,2 los cuales constituyen la guía más importante para la evaluación por parte del médico de cabecera de los pacientes que pudieran padecer de SM. Otro elemento importante en esta investigación es que se resalta la relación SM y envejecimiento, aunque no se argumenta cuáles pudieran ser los nexos entre ellos. Actualmente se considera que sea el endotelio (END) y la disfunción endotelial (DISF) la vía común de cada una de estas alteraciones como lo han propuesto varios autores: niveles elevados de ácidos grasos,3 envejecimiento,4 oxidación de LDL,5 hiperglucemia,6 niveles séricos de adipoquinas7,8 y las especies reactivas del oxígeno.9 Para un abordaje de esta relación SM-E-END sería necesario analizar que la base fisiopatológica del SM es la insulinorresistencia (IR) y que, precisamente, el endotelio tiene una función importante, donde la insulina (INS) logra desempeñar su función.8 En el endotelio se produce el factor de crecimiento similar a la INS (IGF, según sus siglas en inglés)9 y es donde se encuentran proteínas de membrana que sirven de transportadores a la INS. Una vez que se instaura el daño endotelial o la disfunción endotelial (DE), la pérdida...(AU)

El endotelio como órgano diana en la fisiopatología y la terapéutica de la hipertensión arterial / The endothelium as a target organ in pathophysiology and therapy of arterial hypertension

Hemos leído con gran atención el artículo de los autores González Rey y otros, titulado: Disfunción endotelial en una etapa precoz del diagnóstico de hipertensión arterial. Resulta muy interesante el tratamiento de un tema básico de gran interés en la clínica a través del uso de biomarcadores casi siempre a la disposición de nuestros profesionales de la salud en los diferentes niveles de atención como resulta ser el caso de la microalbuminuria.1 El endotelio resulta cada vez de mayor interés para investigadores y médicos de asistencia, pues es el punto de confluencia de las enfermedades vasculares, metabólicas y neurodegenerativas, y es el primer eslabón en el desarrollo de la aterosclerosis. Se conoce que los diferentes factores involucrados en la activación y daño endotelial como las altas concentraciones de ácido úrico,2 los niveles elevados de ácidos grasos,3 el envejecimiento4 y la hiperglicemia,5 son los mismos que contribuyen a posteriori con el desarrollo y las complicaciones de la placa de ateroma. Vale destacar el aporte...(AU)

Interfacial Intermixing and Its Impact on the Energy Band Structure in Interband Cascade Infrared Photodetectors.

Multiple-stage interband cascade infrared photodetector (ICIP) is a new class of semiconductor infrared photodetector that exhibits improved device performance in terms of responsivity and detectivity. The design of the device structure and the electronic structure on superlattices and quantum wells assume abrupt interfaces. However, the emergence of possible interface segregation and atom exchange can only be determined experimentally, impacting the device performance. In this work, the interface atom intermixing and their effects on the energy band structure in a molecular beam epitaxy grown ICIP are studied. Scanning transmission electron microscopy (STEM) reveals atom diffusion and intermixing between the constituent layers of the cascade structure, causing a shift in the quantum state energy levels of the layers and the consequent misalignment of the cascade structures. Combining the STEM observation with high-resolution X-ray diffraction, the alloy composition profiles of the layers are determined. Using the "real" graded composition profiles, the effective band gap of the superlattice absorber and the energy levels of the relaxation region and the tunneling region are recalculated showing a cutoff wavelength of the superlattice absorber 4.93 µm, which is 0.78 µm smaller than that calculated using the nominal step composition profile. However, its agreement is greatly improved with the measured cutoff wavelength of 5.03 µm. The energy level of the narrowest quantum well in the relaxation region is 0.091 eV higher than the conduction miniband of the absorber, which is also consistent with the experiments that the pho-response exits a "turn on" voltage of 0.1 V. The results reported here will help optimize the energy structure design of future ICIP with improved device performance.

Ácido úrico y gamma-glutamiltransferasa como biomarcadores de enfermedad cardiovascular a través del estrés oxidativo / Uric acid and gamma-glutamyltransferase as biomarkers of cardiovascular disease via oxidative stress

Introducción: Las enfermedades cardiovasculares constituyen la principal causa de mortalidad y morbilidad a nivel mundial. Reconocidas como problemas de salud de impacto social, han motivado a muchos científicos a tratar de explicar su patogénesis. Actualmente se plantea de la existencia de otros factores de riesgo, independientemente de los clásicos. Entre estos factores se describen el papel de las altas concentraciones de ácido úrico y la actividad de la enzima gamma-glutamiltransferasa en sangre, biomarcadores de estrés oxidativo. Estos elementos que de manera individual pudieran contribuir a las enfermedades cardiovasculares, parecen tener un efecto sinérgico. Objetivo: Revisar las evidencias que sostienen que altas concentraciones de ácido úrico y la actividad de la enzima gamma-glutamiltransferasa en sangre pueden constituir factores de riesgo que desde el estrés oxidativo contribuyan a las enfermedades cardiovasculares. Métodos: Se recopiló la información a partir de las bases de datos de diferentes buscadores (Medline-Pubmed, Cochrane, Scopus y SciELO) entre el 1 de marzo del 2019 y el 23 de mayo 2020. Conclusiones: Se encontró que, tanto el ácido úrico como la gamma-glutamiltransferasa son productos horméticos que a bajas concentraciones tienen efecto antioxidante en el organismo, pero al elevarse involucran la ocurrencia de procesos oxidativos que conducen a la disfunción endotelial y las enfermedades cardiovasculares(AU)

Introduction: Cardiovascular diseases are the leading cause of mortality and morbidity worldwide. Recognized as a health problem of social impact; they have prompted many scientists to try to explain their pathogenesis. New risk factors are currently acknowledged alongside the classic ones. These factors include the role of high uric acid concentrations and the activity of the enzyme gamma-glutamyltransferase in blood, both of which are biomarkers of oxidative stress. These elements may individually contribute to the development of cardiovascular diseases, and seem to have a synergistic effect. Objective: Review the evidence supporting the idea that high uric acid concentrations and the activity of the enzyme gamma-glutamyltransferase in blood may be risk factors contributing to the development of cardiovascular diseases via oxidative stress. Methods: Data were collected from the databases of various search engines (Medline-Pubmed, Cochrane, Scopus and SciELO) from 1 March 2019 to 23 May 2020. Conclusions: It was found that uric acid and gamma-glutamyltransferase are hormetic products causing an antioxidant effect on the organism at low concentrations. However, when concentrations rise, they are involved in the occurrence of oxidative processes leading to endothelial dysfunction and cardiovascular diseases(AU)

Oxidative Stress and New Pathogenetic Mechanisms in Endothelial Dysfunction: Potential Diagnostic Biomarkers and Therapeutic Targets.

Cardiovascular diseases (CVD), including heart and pathological circulatory conditions, are the world's leading cause of mortality and morbidity. Endothelial dysfunction involved in CVD pathogenesis is a trigger, or consequence, of oxidative stress and inflammation. Endothelial dysfunction is defined as a diminished production/availability of nitric oxide, with or without an imbalance between endothelium-derived contracting, and relaxing factors associated with a pro-inflammatory and prothrombotic status. Endothelial dysfunction-induced phenotypic changes include up-regulated expression of adhesion molecules and increased chemokine secretion, leukocyte adherence, cell permeability, low-density lipoprotein oxidation, platelet activation, and vascular smooth muscle cell proliferation and migration. Inflammation-induced oxidative stress results in an increased accumulation of reactive oxygen species (ROS), mainly derived from mitochondria. Excessive ROS production causes oxidation of macromolecules inducing cell apoptosis mediated by cytochrome-c release. Oxidation of mitochondrial cardiolipin loosens cytochrome-c binding, thus, favoring its cytosolic release and activation of the apoptotic cascade. Oxidative stress increases vascular permeability, promotes leukocyte adhesion, and induces alterations in endothelial signal transduction and redox-regulated transcription factors. Identification of new endothelial dysfunction-related oxidative stress markers represents a research goal for better prevention and therapy of CVD. New-generation therapeutic approaches based on carriers, gene therapy, cardiolipin stabilizer, and enzyme inhibitors have proved useful in clinical practice to counteract endothelial dysfunction. Experimental studies are in continuous development to discover new personalized treatments. Gene regulatory mechanisms, implicated in endothelial dysfunction, represent potential new targets for developing drugs able to prevent and counteract CVD-related endothelial dysfunction. Nevertheless, many challenges remain to overcome before these technologies and personalized therapeutic strategies can be used in CVD management.

Observation of unexpected uniaxial magnetic anisotropy in La2/3Sr1/3MnO3 films by a BaTiO3 overlayer in an artificial multiferroic bilayer.

We studied in detail the in-plane magnetic properties of heterostructures based on a ferroelectric BaTiO3 overlayer deposited on a ferromagnetic La2/3Sr1/3MnO3 film grown epitaxially on pseudocubic (001)-oriented SrTiO3, (LaAlO3)0.3(Sr2TaAlO6)0.7 and LaAlO3 substrates. In this configuration, the combination of both functional perovskites constitutes an artificial multiferroic system with potential applications in spintronic devices based on the magnetoelectric effect. La2/3Sr1/3MnO3 single layers and BaTiO3/La2/3Sr1/3MnO3 bilayers using the pulsed-laser deposition technique. We analyzed the films structurally through X-ray reciprocal space maps and high-angle annular dark field microscopy, and magnetically via thermal demagnetization curves and in-plane magnetization versus applied magnetic field loops at room temperature. Our results indicate that the BaTiO3 layer induces an additional strain in the La2/3Sr1/3MnO3 layers close to their common interface. The presence of BaTiO3 on the surface of tensile-strained La2/3Sr1/3MnO3 films transforms the in-plane biaxial magnetic anisotropy present in the single layer into an in-plane uniaxial magnetic anisotropy. Our experimental evidence suggests that this change in the magnetic anisotropy only occurs in tensile-strained La2/3Sr1/3MnO3 film and is favored by an additional strain on the La2/3Sr1/3MnO3 layer promoted by the BaTiO3 film. These findings reveal an additional mechanism that alters the magnetic behavior of the ferromagnetic layer, and consequently, deserves further in-depth research to determine how it can modify the magnetoelectric coupling of this hybrid multiferroic system.

Local strain-driven migration of oxygen vacancies to apical sites in YBa2Cu3O7-x.

It is well known that in the high-temperature superconductor YBa2Cu3O7-x (YBCO), oxygen vacancies (VO) control the carrier concentration, its critical current density and transition temperature. In this work, it is revealed that VO also allows the accommodation of local strain fields caused by large-scale defects within the crystal. We show that the nanoscale strain associated with Y2Ba4Cu8O16 (Y124) intergrowths-that are common defects in YBCO-strongly affect the venue and concentration of VO. Local probe measurements in conjunction with density-functional-theory calculations indicate a strain-driven reordering of VO from the commonly observed CuO chains towards the bridging apical sites located in the BaO plane and bind directly to the superconducting CuO2 planes. Our findings have strong implications on the physical properties of the YBCO, as the presence of apical VO alters the transfer of carriers to the CuO2 planes, confirmed by changes in the Cu and O core-loss edge probed using electron energy loss spectroscopy, and creates structural changes that affect the Cu-O bonds in the superconducting planes. In addition, the revelation of apical VO also has implications on modulating critical current densities and enhancing vortex pinning.