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Quantized Conductance through Surface States in High Quality Three-Dimensional Dirac Semimetal Cd3As2 Nanowire/Nanoribbon p-n Junctions

2026-05-31T15:00:00Z

Title: Quantized Conductance through Surface States in High Quality Three-Dimensional Dirac Semimetal Cd3As2 Nanowire/Nanoribbon p-n Junctions Author(s): An, Sungjin; Siu, Zhuo Bin; Kaladzhyan, Vardan; Bardarson, Jens H.; Lee, Sunghun; Lee, Myoung-Jae; Park, Kidong; Park, Jeunghee; Jalil, Mansoor B. A.; Seo, Jungpil; Jung, Minkyung Abstract: We report the observation of quantized conductance in high-mobility three-dimensional Dirac semimetal Cd3As2 nanowire and nanoribbon p-n junctions. By employing suspended device geometries with dual local gates, we form tunable p-n junctions and realize ballistic transport across sub-micron channel lengths. In a wide nanoribbon device with a channel width of similar to 330 nm, conductance plateaus appear at integer multiples of 2e(2)/h in the n-n regime under high magnetic fields. Numerical simulations suggest that these features represent unresolved spin split subbands due to the smaller subband spacing in wider channels and support the interpretation that the observed quantization may originate from surface-state-dominated conduction. In contrast, narrower nanoribbons and nanowires exhibit conductance steps of 1e(2)/h, demonstrating spin-resolved subbands likely due to enhanced confinement effects. From spin-resolved subband spectroscopy, we extract an effective Land & eacute; g-factor of similar to 43 for the first subband in the bulk gap, establishing these nanostructures as a prospective platform for fault-tolerant quantum electronics.

건식 도포를 이용한 RE-Fe-B계 소결자석의 제조방법 및 이를 통하여 제조된 RE-Fe-B계 소결자석

Title: 건식 도포를 이용한 RE-Fe-B계 소결자석의 제조방법 및 이를 통하여 제조된 RE-Fe-B계 소결자석 Author(s): 이동현; 노종욱; 김정민; 김동환

Relationship between Nd-rich phase and oxygen content for additive-free sintering with regenerated powder from magnet sludge waste

2026-01-31T15:00:00Z

Title: Relationship between Nd-rich phase and oxygen content for additive-free sintering with regenerated powder from magnet sludge waste Author(s): Galkin, Vitalii; Kim, Jeongmin; Roh, Jong Wook; Kim, Dongsoo Abstract: Recycling of Nd-Fe-B magnet sludge into high-performance powders is critical for sustainable rare-earth resource utilization. In this study, Nd-Fe-B powders were regenerated via a reduction-diffusion process and subjected to different washing treatments to investigate their effects on microstructure, phase composition, and magnetic properties. Conventional water washing at larger scales resulted in increased oxidation, depletion of Nd-rich phase, while requiring prolonged washing cycles and excessive water consumption. In contrast, scale up washing with an NH4NO3 solution in methanol effectively minimized oxidation, preserved Nd-rich, and maintained a uniform 1–2μm particle size distribution. The resulting powders exhibited superior magnetic properties, including high coercivity, enhanced squareness, and an improved maximum energy product. The NH4NO3 in MeOH washing method also demonstrated higher yield, improved processing efficiency, and scalability, highlighting its potential as a practical approach for sustainable production of regenerated Nd-Fe-B powders. These findings provide a promising pathway for recycling magnet sludge into high-quality powders suitable for sintered magnet fabrication, contributing to resource conservation and the advancement of rare-earth recycling technologies.

Low-temperature and low-pressure sinter-bonding for thermoelectric generator devices using Cu nanoparticle paste

2026-01-31T15:00:00Z

Title: Low-temperature and low-pressure sinter-bonding for thermoelectric generator devices using Cu nanoparticle paste Author(s): Chung, Seok-Hwan; Park, Jong Ho; Kim, Jong Tae; Kim, Jeongmin; Kim, Dong Hwan Abstract: For the successful commercialization of thermoelectric generator (TEG) devices, efficient thermoelectric materials and reliable electrode bonding with high thermal stability are essential. In this study, we synthesized conducting pastes based on Cu nanoparticles and developed a low-temperature and low-pressure sinter-bonding method for TEG devices using these pastes. Cu nanoparticle paste (CNP) bonding layer exhibited high shear strength up to 16.4 MPa, and low thermal contact resistance of 6.4 × 10−7 m2K/W. A 4-chip Bi2Te3-based TEG device bonded using CNP achieved a power density of 0.76 W/cm2 under a large temperature gradient of 330 °C. The CNP bonding joints retained their physical properties at temperatures up to 350 °C, thereby extending the operational temperature range of current Bi2Te3-based TEG devices. This approach overcomes the limitations of conventional Sn-based solders without relying on costly Ag nanoparticles, while achieving improved high-temperature performance of TEG devices. © 2026 The Authors.