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1. High-current, high-voltage AlN Schottky barrier diodes

   https://doi.org/10.35848/1882-0786/ad81c9  

   Quiñones, C_E; Khachariya, D.; Reddy, P.; Mita, S.; Almeter, J.; Bagheri, P.; Rathkanthiwar, S.; Kirste, R.; Pavlidis, S.; Kohn, E.; et al (October 2024, Applied Physics Express)

   AlN Schottky barrier diodes with low ideality factor (<1.2), low differential ON-resistance (<0.6 mΩ cm²), high current density (>5 kA cm⁻²), and high breakdown voltage (680 V) are reported. The device structure consisted of a two-layer, quasi-vertical design with a lightly doped AlN drift layer and a highly doped Al_0.75Ga_0.25N ohmic contact layer grown on AlN substrates. A combination of simulation, current–voltage measurements, and impedance spectroscopy analysis revealed that the AlN/AlGaN interface introduces a parasitic electron barrier due to the conduction band offset between the two materials. This barrier was found to limit the forward current in fabricated diodes. Further, we show that introducing a compositionally-graded layer between the AlN and the AlGaN reduces the interfacial barrier and increases the forward current density of fabricated diodes by a factor of 10⁴. 

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2. Dual-phase superconductivity in high-pressure high-temperature synthesized TaNbZrHfTi

   https://doi.org/10.1063/5.0214797  

   Sereika, Raimundas; Iwan, Seth; Baker, Paul_A; Bi, Wenli; Vohra, Yogesh_K (June 2024, AIP Advances)

   We report on a novel TaNbZrHfTi-based high entropy alloy (HEA) which demonstrates distinctive dual-phase superconductivity. The HEA was synthesized under high pressures and high temperatures starting from a ball milled mixture of elemental metals in a large-volume Paris–Edinburgh cell with P ≈ 6 GPa and T = 2300 K. The synthesized HEA is a phase mixture of BCC (NbTa)0.45(ZrHfTi)0.55 with Tc1 = 6 K and FCC (NbTa)0.04(ZrHfTi)0.96 with Tc2 = 3.75 K. The measured magnetic field parameters for the HEA are lower critical field, Hc1(0) = 31 mT, and a relatively high upper critical field, Hc2(0) = 4.92 T. This dual-phase system is further characterized by the presence of a second magnetization peak, or the fishtail effect, observed in the virgin magnetization curves. This phenomenon, which does not distort the field-dependent magnetization hysteresis loops, suggests intricate pinning mechanisms that could be potentially tuned for optimized performance. The manifestation of these unique features in HEA superconductivity reinforces phase-dependent superconductivity and opens new avenues in the exploration of novel superconducting materials. 

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3. Visible-light-induced ATRP under high-pressure: synthesis of ultra-high-molecular-weight polymers

   https://doi.org/10.1039/d3cc04982e  

   Bernat, Roksana; Szczepaniak, Grzegorz; Kamiński, Kamil; Paluch, Marian; Matyjaszewski, Krzysztof; Maksym, Paulina (January 2024, Chemical Communications)

   Using high-pressure and light irradiation, we innovatively synthesized UHMW polymers, overcoming traditional ATRP limitations. 

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4. High-resolution, high-throughput analysis of Drosophila geotactic behavior

   https://doi.org/10.1242/jeb.248029  

   Canic, Tijana; Lopez, Juan; Ortiz-Vega, Natalie; Zhai, R Grace; Syed, Sheyum (February 2025, Journal of Experimental Biology)

   ABSTRACT Drosophila’s innate response to gravity, geotaxis, has been used to assess the impact of aging and disease on motor performance. Despite its rich history, fly geotaxis continues to be largely measured manually and assessed through simplistic metrics, limiting analytic insights into the behavior. Here, we have constructed a fully programmable apparatus and developed a multi-object tracking software capable of following sub-second movements of individual flies, thus allowing quantitative analysis of geotaxis. The apparatus monitors 10 fly cohorts simultaneously, with each cohort consisting of up to 7 flies. The software tracks single flies during the entire run with ∼97% accuracy, yielding detailed climbing curve, speed and movement direction with 1/30 s resolution. Our tracking permits the construction of multi-variable metrics and the detection of transitory movement phenotypes, such as slips and falls. The platform is therefore poised to advance Drosophila geotaxis assay into a comprehensive assessment of locomotor behavior. 

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5. Superior High‐Temperature Strength in a Supersaturated Refractory High‐Entropy Alloy

   https://doi.org/10.1002/adma.202102401  

   Feng, Rui; Feng, Bojun; Gao, Michael_C; Zhang, Chuan; Neuefeind, Joerg_C; Poplawsky, Jonathan_D; Ren, Yang; An, Ke; Widom, Michael; Liaw, Peter_K (October 2021, Advanced Materials)

   Abstract Refractory high‐entropy alloys (RHEAs) show promising applications at high temperatures. However, achieving high strengths at elevated temperatures above 1173K is still challenging due to heat softening. Using intrinsic material characteristics as the alloy‐design principles, a single‐phase body‐centered‐cubic (BCC) CrMoNbV RHEA with high‐temperature strengths (beyond 1000 MPa at 1273 K) is designed, superior to other reported RHEAs as well as conventional superalloys. The origin of the high‐temperature strength is revealed by in situ neutron scattering, transmission‐electron microscopy, and first‐principles calculations. The CrMoNbV's elevated‐temperature strength retention up to 1273 K arises from its large atomic‐size and elastic‐modulus mismatches, the insensitive temperature dependence of elastic constants, and the dominance of non‐screw character dislocations caused by the strong solute pinning, which makes the solid‐solution strengthening pronounced. The alloy‐design principles and the insights in this study pave the way to design RHEAs with outstanding high‐temperature strength. 

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