https://scholar.dgist.ac.kr/handle/20.500.11750/15732 2026-07-01T08:25:03Z https://scholar.dgist.ac.kr/handle/20.500.11750/60420 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. 2026-05-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59294 Title: Radio-Frequency Detection of Fabry–Pérot Interference and Quantum Capacitance in Long-Channel Three-Dimensional Dirac Semimetal Cd3As2Nanowires Author(s): An, Sung Jin; Kim, Jisu; Jung, Myung-chul; Park, Kidong; Park, Jeunghee; Shim, Seung-bo; Kim, Hakseong; Siu, Zhuo Bin; Jalil, Mansoor B.A.; Schönenberger, Christian; Myoung, Nojoon; Seo, Jungpil; Jung, Minkyung Abstract: We demonstrate phase-coherent transport in suspended long-channel Cd3As2 nanowire devices using both direct current (DC) transport and radiofrequency (RF) reflectometry measurements. By integrating Cd3As2 nanowires with on-chip superconducting LC resonators, we achieve sensitive detection of both resistance and quantum capacitance variations. In a long-channel device (L ≈ 1.8 μm), clear Fabry–Pérot (FP) interference patterns are observed in both DC and RF measurements, providing strong evidence for ballistic electron transport. RF reflectometry reveals gate-dependent modulations of the resonance frequency arising from quantum capacitance oscillations induced by changes in the density of states and FP interference. These oscillations exhibit a quasi-periodic structure that closely correlates with the FP patterns in DC transport measurements. In another device of a Cd3As2 nanowire Josephson junction (L ≈ 730 nm, superconducting Al contacts), FP interference patterns are too weak to be resolved in DC conductance but are detectable using RF reflectometry. These results demonstrate the high quality of our Cd3As2 nanowires and the versatility of RF reflectometry, establishing their potential for applications in topological quantum devices such as Andreev qubits or gatemon architectures. 2025-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/57352 Title: Enhanced magnetization by defect-assisted exciton recombination in atomically thin CrCl3 Author(s): Zhang, Xin-Yue; Graham, Thomas K. M.; Bae, Hyeonhu; Wang, Yu-Xuan; Delegan, Nazar; Ahn, Jonghoon; Wang, Zhi-Cheng; Regner, Jakub; Watanabe, Kenji; Taniguchi, Takashi; Jung, Minkyung; Sofer, Zdeněk; Tafti, Fazel; Awschalom, David D.; Heremans, F. Joseph; Yan, Binghai; Zhou, Brian B. Abstract: Two-dimensional semiconductors present unique opportunities to intertwine optical and magnetic functionalities and to tune these performances through defects and dopants. Here, we integrate exciton pumping into a quantum sensing protocol on nitrogen-vacancy centers in diamond to image the optically induced transient stray fields in few-layer, antiferromagnetic CrCl3. We discover that exciton recombination enhances the in-plane magnetization of the CrCl3 layers, with a predominant effect in the surface monolayers. Concomitantly, time-resolved photoluminescence measurements reveal that nonradiative exciton recombination intensifies in atomically thin CrCl3 with tightly localized, nearly dipole-forbidden excitons and amplified surface-to-volume ratio. Supported by experiments under controlled surface exposure and density functional theory calculations, we interpret the magnetically enhanced state to result from a defect-assisted Auger recombination that optically activates electron transfer between water vapor related surface impurities and the spin-polarized conduction band. Our work validates defect engineering as a route to enhance intrinsic magnetism in single magnetic layers and opens an experimental platform for studying optically induced, transient magnetism in condensed matter systems. © 2024 American Physical Society. 2024-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/56556 Title: Full-dry flipping transfer method for van der waals heterostructure Author(s): Kim, Dohun; Kim, Soyun; Cho, Yanni; Lee, Jaesung; Watanabe, Kenji; Taniguchi, Takashi; Jung, Minkyung; Falson, Joseph; Kim, Youngwook Abstract: We present a novel flipping transfer method for van der Waals heterostructures, offering a significant advancement over previous techniques by eliminating the need for polymers and solvents. Here, we utilize commercially available gel film and control its stickiness through oxygen plasma and UV-Ozone treatment, also effectively removing residues from the gel film surface. The cleanliness of the surface is verified through atomic force microscopy. We investigate the quality of our fabricated devices using magnetotransport measurements on graphene/hBN and graphene/α-RuCl3 heterostructures. Remarkably, graphene/hBN devices produced with the flipping method display quality similar to that of fully encapsulated devices. This is evidenced by the presence of a symmetry-broken state at 1 T. Additionally, features of the Hofstadter butterfly were also observed in the second devices. In the case of graphene/α-RuCl3, we observe quantum oscillations with a beating mode and two-channel conduction, consistent with fully encapsulated devices. © 2023 Korean Physical Society 2024-02-29T15:00:00Z