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  • Pressure engineered optical properties as well as presssure induced emergent superconductivity are revealed in II-IV-V2 semiconductor ZnSiP2, which demonstrate vivid structure–property relationships. Especially, along with a structural phase transition from tetragonal to cubic phase under compression, ZnSiP2 evolves from a photovoltaic semiconductor into a superconductor.

    • Yifang Yuan
    • Xiangde Zhu
    • Zhaorong Yang
    Article Open Access
  • The semiconductor SnSe hosts a unique multivalley electronic band structure, offering rich physical phenomena for various applications. Especially its excellent thermoelectric properties are ceaselessly under great attention. By employing pressure-dependent infrared spectroscopy combined with density functional theory calculations, the evolution of the multivalley is mapped under external pressure for different self-dopings. The presented diagram summarizes the findings. In lightly doped SnSe, a phase transition from a semiconductor to a semimetal is observed by increasing the pressure. However, for heavily doped SnSe, altering the Fermi surface, successive Lifshitz transitions take place under pressure, further activating the multivalley physics.

    • Tobias Biesner
    • Weiwu Li
    • Martin Dressel
    Article Open Access
  • The broken inversion symmetry and time-reversal symmetry along with the large spin–orbit interactions in monolayer MoS2 make it an ideal candidate for novel valleytronic applications. The present study demonstrates the fabrication of a monolayer MoS2 field-effect transistor employing [Co/Pt] multilayer electrodes. Integration of PMA electrodes results in very-low Schottky barrier height in MoS2-based field-effect transistor devices.

    • S. Gupta
    • F. Rortais
    • M. Shiraishi
    Article Open Access
  • we report a field-effect device with a graphene/MoSe2 channel layer and high-k ion-gel gate dielectric. The device shows a high carrier mobility (~247 cm2/V ∙ s), a high on/off ratio (3.3 × 104), and ambipolar behavior that are controlled by an applied gate voltage. The strong gating effect of the device results in higher external quantum efficiency (EQE) (66.3%), photoresponsivity (285.0 mA/W), and gate-tuning ratio (1.50 μA/V) compared to pristine devices. Therefore, our graphene/MoSe2 barristor device can be a suitable candidate for use in ambipolar transistors and gate-tunable broad-area photodetectors.

    • Gwangtaek Oh
    • Ji Hoon Jeon
    • Bae Ho Park
    Article Open Access
  • We introduced spintronics-based synapses (spin-S) by utilizing a stripe domain ensuring its highly linear and symmetric weight responses, together with domain-wall motion-based neurons (spin-N) for activation functions. In addition, a crossbar array architecture for the spin-S/N has been proposed and experimentally demonstrated. A simple pattern-classification task was tested using an integrated network of electrically connected spin-S and spin-N to mimic a human brain. Our experimental findings provide a new avenue toward establishing more efficient neural network systems with spintronic devices.

    • Seungmo Yang
    • Jeonghun Shin
    • Jin Pyo Hong
    Article Open Access
  • Spin mixing conductance ( $$g_r^{ \uparrow \downarrow }$$ g r ) and spin interface transparency at the interface of epitaxial Co2Fe0.4Mn0.6Si Heusler alloy and Pt has be studied by inverse spin Hall effect and spin pumping measurements. Highest value of $$g_r^{ \uparrow \downarrow }$$ g r = 1.70 × 1020 m−2 is observed compared to any other ferromagnetic -Pt heterostructures. Further, a high value of spin interface transparency (~83%) is observed, which makes Co2Fe0.4Mn0.6Si/Pt heterostructure a potential candidate for the development of power efficient spintronics devices.

    • Braj Bhusan Singh
    • Koustuv Roy
    • Subhankar Bedanta
    Article Open Access
  • A hitherto unappreciated shear-strain-mediated magnetoelectric coupling effect with highly tunable ferromagnetic resonance by electric field is demonstrated by using the ferroelastic domain engineering of the ferroelectric substrate. The pure shear strain, instead of magnetic field and electric current, control of Kerr signal with superior stability and nonvolatile behaviors shows promising applications in next-generation lightweight, energy efficient magnetoelectric microwave devices and spintronic devices.

    • Ming Zheng
    • Takamasa Usami
    • Tomoyasu Taniyama
    Article Open Access
  • Infrared spectral and spatial imaging configurations were developed based on near-infrared graphene quantum dots with ultranarrow half-width (FWHM = 21 nm). The spectral imaging is obtained without a spectrometer and the spatial imaging exceeds the limits of resolution (superresolved imaging). The superresolved sensing is obtained due to the unique temporal and spectral properties of the quantum dot.

    • Zhen Wang
    • Xuezhe Dong
    • Zeev Zalevsky
    Article Open Access
  • a Aging-time dependent saturation magnetostriction for Fe73Ga27 random polycrystals. Bright-field images for the b 1373 K-quenched, c 1 h-aged and d 12 h-aged Fe73Ga27 random polycrystals. e Figure of merit as a function of aging time for Fe81Ga19 random polycrystals. f Comparison of saturation magnetostriction among our optimally aged Fe–Ga random polycrystals, the quenched random polycrystals doped with a third element and the single crystals.

    • Junming Gou
    • Tianyu Ma
    • Xiaobing Ren
    Article Open Access
  • Stretchable and wearable Ag-PTFE conductors were fabricated by the simple and mature co-sputtering process with variations in the DC/RF power ratio applied to the Ag and PTFE target. A stretching test was conducted 40% strain under all conditions and reversible to confirm that the hysteresis and stretchability were good for DC 5 W:RF 40 W.

    • Sunyoung Yoon
    • Yong Jun Kim
    • Han-Ki Kim
    Article Open Access
  • We present an in vitro model of the peripheral nervous system by establishing a coculture of motor neurons (MNs) and Schwann cells (SCs) in a microengineered hydrogel scaffold. This 3D microenvironment allowed the axons of MNs to actively interact with SCs during their growth and maturation. Treating the MN–SC coculture model with ascorbic acid induced myelin formation on axon fibers. Moreover, this can be reversed by treating myelinated nerve fibers with glial growth factor to potentially block the formation of the myelin sheath and induce demyelination. Our model may offer new opportunities to study pathophysiological processes involved in neurodegenerative diseases.

    • Sunghee Estelle Park
    • Jinchul Ahn
    • Seok Chung
    Article Open Access
  • A novel 3D self-supported integrated electrode of Co4N@CoSA/N-CNT/CC is designed for admirable HER electrocatalysis. Experiment and theory studies reveal that the suitable d-band center and electron-charge transfer optimized by Co4N nanoparticles and single-atom Co in the electrocatalyst contribute to an excellent performance. This electrode requires overpotentials of only 78 and 86 mV at 10 mA cm−2 in acidic and basic electrolytes, respectively. Notably, Co4N@CoSA/N-CNT/CC also exhibits superior long-term stability in acidic and alkaline medium, the decrease in current density after continuous electrocatalysis for 50 h are only 5% and 11%, respectively.

    • Bo Cao
    • Minghao Hu
    • Jun Zhang
    Article Open Access
  • Combining Lorentz transmission electron microscopy and micromagnetic simulations, we discover a high-density homochiral Néel-type skyrmion phase in a Pt/Co/Ru/Pt/CoFeB/Ru magnetic multilayer structure that is stable at high temperatures up to 733 K. The domain phase in this system can be modulated between a high-density skyrmion phase, an isolated skyrmion phase, or a stripe domain phase by appropriate tuning of external and material parameters. This finding suggests that multilayer Néel-type skyrmions can be utilized in nonvolatile spin-based electronic devices that require operation at elevated temperatures.

    • Hee Young Kwon
    • Kyung Mee Song
    • Jun Woo Choi
    Article Open Access
  • Ultra-fast electrochromic supercapacitors (ECSs) are demonstrated based on mesoporous WO3 prepared by evaporation-induced self-assembly (EISA). Mesoporous WO3 based ECSs show excellent electrochromic and supercapacitor performances under fast operating condition. Furthermore, printing assisted EISA is introduced to produce patterned mesoporous WO3 for ECS displays (ECSDs). The resulting ECSDs have great potential as next-generation smart electrochemical components.

    • Keon-Woo Kim
    • Tae Yong Yun
    • Jin Kon Kim
    Article Open Access
  • There is a fundamental divide in symmetry between crystalline and glassy materials, where the structural disorder in glass leads to unique material properties and a myriad of applications. The provision of metrics for describing the order within disorder remains, however, an open challenge, especially on length scales beyond the nearest neighbor that are characterized by rich structural complexity. Here, we address this challenge by applying the method of persistent homology to characterize the structure of silica glass. The structural disorder is systematically engineered by preparing the glass under different high-pressure and temperature conditions, which impacts on the low-frequency vibrational and thermodynamic properties.

    • Yohei Onodera
    • Shinji Kohara
    • Osami Sakata
    Article Open Access
  • Zr2SP2O12 has unique negative thermal expansion behavior involving both phase transition- and framework-type mechanisms. The volumetric CTE of α-Zr2SP2O12 is approximately −70 ppm/K during the isosymmetric phase transition in the temperature range of 393–453 K. This value can be improved by decreasing the proportion of sulfur. The minimum volumetric CTE of α-Zr2S0.9P2O12-δ is approximately −108 ppm/K.

    • Toshihiro Isobe
    • Yuko Hayakawa
    • Akira Nakajima
    Article Open Access
  • Flexible high-performance hybrid graphene photodetectors have been developed by introducing both perovskite materials and gold nanostars. The developed photodetectors exhibit significantly enhanced optoelectronic performances due to the synergistic effects of hybrid system including high light absorption of perovskites and strong plasmonic effects of gold nanostars with high mechanical stability, which extends the range of their practical applications.

    • Yoon Ho Lee
    • Seungyoung Park
    • Joon Hak Oh
    Article Open Access
  • We report on the formation and rupture of CFs through Ag ion migration inside a single-crystalline 2D van der Waals (vdW) solid electrolyte material within an ECM device structure. This study provides clear experimental evidence that CFs consisting of Ag can be formed inside single-crystalline 2D layered chromium thiophosphate (CrPS4) and their configuration can be changed by an applied voltage. Density functional theory calculations confirm that the Ag ion migration is an energetically favorable process. The electrically induced changes in Ag CFs inside single-crystalline CrPS4 raise the possibility of a reliable ECM device that exploits the properties of two-dimensionally confined materials.

    • Mi Jung Lee
    • Sung-Hoon Kim
    • Bae Ho Park
    Article Open Access
  • The formation of the conductive region (n+ layer) in (Zn,Ba)SnO3 (ZBTO) semiconductor is proposed to achieve high performance of thin-film transistors (TFTs). The aluminum metal capping layer is adopted to enhance the field-effect mobility of ZBTO TFTs. The capped Al layer takes out oxygen in the back-channel region, where the AlOx interlayer is formed. As a result, the field-effect mobility of Al-capped ZBTO TFTs is remarkably increased from 20.8 to 153.4 cm2/Vs. Furthermore, the Al-capped ZBTO TFTs are stable even when exposed to air for 3 months.

    • Ji-Min Park
    • Hyoung-Do Kim
    • Hyun-Suk Kim
    Article Open Access