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Recent advances in semiconductor based electronic devices can be attributed to the technological demands of ever increasing, application specific markets. These rapidly evolving markets for devices such as displays, wireless communication, photovoltaics, medical devices, etc. are demanding electronic devices that are increasingly thinner, smaller, lighter and flexible. High-quality, III-V epitaxial thin-films deposited on single-crystal substrates have yielded extremely high-performance, but are extremely expensive and rigid. Here we demonstrate heteroepitaxial deposition of GaAs thin-films on large-grained, single-crystal-like, biaxially-aligned, flexible, metallic substrates. We use molecular beam epitaxy (MBE) for the controlled growth of high quality GaAs layers on lattice matched Ge capped, flexible metal substrates. The structural, optical, interfacial and electrical characteristics and properties of the heteroepitaxial GaAs layers are analyzed and discussed. The results show that heteroepitaxial GaAs layers with good crystalline and optoelectronic properties can be realized for flexible, III-V based semiconductor devices. III-V materials integrated on large-grained, single-crystal-like, flexible, metallic substrates offer a potential route towards fabrication of large-area, high-performance electronic devices.

Background and Clinical Significance: Takotsubo cardiomyopathy (TCM), an acute stress-induced left ventricular dysfunction, stems from catecholaminergic surges leading to transient myocyte stunning, calcium overload, and microvascular dysregulation. Although most cases resolve spontaneously, roughly 10% deteriorate into fulminant cardiogenic shock, warranting mechanical circulatory support (MCS). Impella® provides direct transvalvular LV unloading but carries elevated risks of hemolysis, vascular compromise, and thrombogenicity. Conversely, the intra-aortic balloon pump (IABP) enhances diastolic coronary perfusion and marginally reduces afterload via counterpulsation, albeit with less potent LV decompression. Optimal MCS selection in TCM-associated shock therefore hinges on balancing hemodynamic benefits against procedural morbidity. Case Presentation: A 72-year-old female with coronary artery disease, paroxysmal atrial fibrillation (status post–left atrial appendage occlusion), and stage 3 chronic kidney disease presented with anterior ST-segment elevations (V2–V4) and troponin I >1000 ng/L, progressing rapidly to cardiogenic shock and respiratory failure. Coronary angiography revealed mild luminal irregularities, while echocardiography demonstrated severely reduced ejection fraction (5–10%) with characteristic apical ballooning. Refractory elevations in pulmonary capillary wedge pressure, despite escalating inotropes and vasopressors, prompted IABP insertion for partial LV offloading. Over one week, her ejection fraction improved to 35%, facilitating weaning from pressor support, extubation, and discharge on guideline-directed medical therapy. Conclusions: In TCM complicated by shock, meticulous MCS selection is paramount. Although Impella confers more robust unloading, heightened device-related complications may be unjustified in a largely reversible disease. IABP can sufficiently stabilize hemodynamics, enable myocardial recovery, and mitigate morbidity, underscoring the importance of individualized decision-making in TCM-related shock. Importantly, no trial has shown that MCS confers a proven long-term mortality benefit beyond initial hemodynamic rescue.

Although high-temperature superconductor cuprates have been discovered for more than 25 years, superconductors for high-field application are still based on low-temperature superconductors, such as Nb 3 Sn. The high anisotropies, brittle textures and high manufacturing costs limit the applicability of the cuprates. Here we demonstrate that the iron superconductors, without most of the drawbacks of the cuprates, have a superior high-field performance over low-temperature superconductors at 4.2 K. With a CeO 2 buffer, critical current densities >10 6 A cm −2 were observed in iron-chalcogenide FeSe 0.5 Te 0.5 films grown on single-crystalline and coated conductor substrates. These films are capable of carrying critical current densities exceeding 10 5  A cm −2 under 30 tesla magnetic fields, which are much higher than those of low-temperature superconductors. High critical current densities, low magnetic field anisotropies and relatively strong grain coupling make iron-chalcogenide-coated conductors particularly attractive for high-field applications at liquid helium temperatures. Iron-based superconductors have the potential to carry higher currents and withstand higher magnetic fields than present-day superconducting cables. Using an approach developed for cuprates, Si et al . improve the high-field performance of iron-based superconductors well beyond that of conventional superconductors.

This work presents a dielectric material-based optical Tamm state (OTS) excitation technique with modified dispersion characteristics for photonic spin hall effect (PSHE) enhancement. The dispersion analysis of the structure is carried out to validate OTS’s localization and corresponding PSHE generation for a given polarization at 632.8 nm incident wavelength. The exceptional points are optimized by considering thickness-dependent angular dispersion analysis. PSHE-based transverse displacement (PSHE-TD) is dependent on the defect layer thickness. The optimized structure provides 10.73  × λ (or 6.78  μ m) PSHE-TD at an incidence angle of 41.86 ∘ . The PSHE-TD of the optimized structure is sufficiently high due to the much narrower resonance than the plasmonic-based structures. Further, the structure’s potential to function as a PSHE-TD-based optical sensor is assessed. The optimized structure shows an analytical average sensitivity of about 43,789  μ m/RIU showing its capability to detect the analytes with refractive index variations in the 10 - 4 range. The structure demonstrates a three-time sensitivity improvement compared to similar resonance designs. Considering only dielectric materials in the proposed structure and considerably enhanced PSHE-TD, the development of highly efficient PSHE-TD-assisted commercial structures is anticipated.

We use atomically resolved scanning transmission electron microscopy and electron energy loss spectroscopy to determine the atomic-scale structural, chemical and electronic properties of artificial engineered defects in irradiated-annealed high temperature superconducting wires based on epitaxial Y(Dy)BCO film. We directly probe the oxygen vacancy defects in both plane and chain sites after irradiation with 18-meV Au ions. The plane site vacancies are reoccupied during post-annealing treatment. Our results demonstrate the dynamic reversible behavior of oxygen point defects, which explains the depression and recovery of self-field critical current and critical temperature in irradiation-annealing process. These findings reveal the strong effect of oxygen vacancies in different sites on the superconductivity properties of irradiated Y(Dy)BCO film, and provide important insights into defects engineering of 2G HTS coil wires.

In this manuscript, a heterostructure-based topological nanophotonic structure is proposed for improved sensing performance. The topological effect is realized by connecting two dissimilar one-dimensional photonic crystal structures having overlapped photonic bandgaps. The structural parameters are optimized to regulate and alter the dispersion characteristics, which results in the opposite Zak phases. This demonstrates a robust topologsical interface state excitation at a 1737 nm operating wavelength. Further, a topological cavity structure having resonance mode at 1659 nm is formed by replacing the interface layers with a defect layer. The mode excitation is confirmed by analyzing the electric field confinement at the interface. The sensing capability of the structure is analytically evaluated by infiltrating different analytes within the cavity. The analytical results demonstrate the device’s average sensitivity of around 774 nm/Refractive index unit (RIU) along with an average high Q-factor and figure of merit of around 5.2 × 10 4 and 2.6234 × 10 4 RIU −1 , respectively. Because of the higher interface mode field confinement, the proposed structure exhibits a 92% higher sensitivity, 98% improved Quality factor, 206% improvement in figure of merit, and 86% higher interface field confinement than conventional Fabry–Perot resonator structures. Thus, the proposed topological cavity structure shows its broad sensing ability (Refractive Index: 1.3–1.6) along with a low-cost, simple fabrication and characterization process, promoting the development of highly sensitive planner nanophotonic devices.

In this manuscript, a novel photonic crystal resonator (PhCR) structure having an exponentially graded refractive index profile is proposed to regulate and alter the dispersion characteristics for the first time. The structure comprises silicon material, where porosity is deliberately introduced to modulate the refractive index profile locally. The structural parameters are optimized to have a resonant wavelength of 1550 nm. Further, the impact of various parameters like incidence angle, defect layer thickness, and analyte infiltration on device performance is evaluated. Finally, the sensing capability of the proposed structure is compared with the conventional step index-based devices. The proposed structure exhibits an average sensitivity of 54.16 nm/RIU and 500.12 nm/RIU for step index and exponentially graded index structures. This exhibits the generation of a lower energy resonating mode having 825% higher sensitivity than conventional resonator structures. Moreover, the graded index structures show a 45% higher field confinement than the conventional PhCR structure.

This paper takes a new look at the predictability of stock market returns with risk measures. We find a significant positive relation between average stock variance (largely idiosyncratic) and the return on the market. In contrast, the variance of the market has no forecasting power for the market return. These relations persist after we control for macroeconomic variables known to forecast the stock market. The evidence is consistent with models of time-varying risk premia based on background risk and investor heterogeneity. Alternatively, our findings can be justified by the option value of equity in the capital structure of the firms.

This manuscript presents a dielectric resonator structure with altered dispersion characteristics to enhance the photonic spin Hall effect (PSHE). The structural parameters are optimized to enhance the PSHE at 632.8 nm operating wavelength. The thickness-dependent angular dispersion analysis is carried out to optimize the structure and obtain the exceptional points. The PSHE-induced spin splitting shows a high sensitivity to the optical thickness of the defect layer. This gives a maximum PSHE-based transverse displacement (PSHE-TD) of around 56.66 times the operating wavelength at an incidence angle of 61.68°. Moreover, the structure’s capability as a PSHE-based refractive index sensor is also evaluated. The analytical results demonstrate an average sensitivity of around 33,720 μm/RIU. The structure exhibits around five times higher PSHE-TD and approximately 150% improvement in sensitivity than the recently reported values in lossy mode resonance structures. Due to the purely dielectric material-assisted PhC resonator configurations and significantly higher PSHE-TD, the development of low-cost PSHE-based devices for commercial applications is envisaged.