A5041039368- Topological Materials and Phenomena
- Graphene research and applications
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Advanced Condensed Matter Physics
- MXene and MAX Phase Materials
- Iron-based superconductors research
- Physics of Superconductivity and Magnetism
- Neutrino Physics Research
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Surface and Thin Film Phenomena
- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Quantum many-body systems
- Rare-earth and actinide compounds
- Advanced Memory and Neural Computing
- Intellectual Capital and Performance Analysis
- Electronic and Structural Properties of Oxides
- Neuroscience and Neural Engineering
- Integrated Circuits and Semiconductor Failure Analysis
- Image and Video Quality Assessment
- Crystallization and Solubility Studies
- Quantum Dots Synthesis And Properties
- Inorganic Chemistry and Materials
Yonsei University
2017-2025
Diamond Light Source
2019-2024
Gyeongsang National University
2021-2024
Seoul National University
2012-2024
The University of Tokyo
2021
Institute for Basic Science
2014-2021
Pohang University of Science and Technology
2004-2018
Korea Electronics Technology Institute
1997-2013
NTT (United States)
2004
NTT Basic Research Laboratories
2004
Two-dimensional (2D) van-der-Waals semiconductors have emerged as a class of materials with promising device characteristics owing to the intrinsic bandgap. For realistic applications, ideal is modify bandgap in controlled manner by mechanism that can be generally applied this materials. Here, we report observation universally tunable family bulk 2H transition metal dichalcogenides (TMDs) situ surface doping Rb atoms. A series angle-resolved photoemission spectra unexceptionally shows TMDs...
The layered van der Waals antiferromagnet MnBi${}_{2}$Te${}_{4}$ has been predicted previously to realize the first intrinsic magnetic topological insulator. Here, authors report spin- and angle-resolved photoemission experiments for MnBi${}_{2}$Te${}_{4}$(0001) surface, revealing a surface state in bulk band gap providing evidence interplay between exchange interaction spin-orbit coupling electronic structure. thus constitutes promising candidate exploit of states order spintronic device concepts.
Combinations of non-trivial band topology and long-range magnetic order hold promise for realizations novel spintronic phenomena, such as the quantum anomalous Hall effect topological magnetoelectric effect. Following theoretical advances material candidates are emerging. Yet, a compound with band-inverted electronic structure an intrinsic net magnetization remains unrealized. MnBi$_2$Te$_4$ is candidate first antiferromagnetic insulator progenitor modular (Bi$_2$Te$_3$)$_n$(MnBi$_2$Te$_4$)...
Topological quantum materials coupled with magnetism can provide a platform for realizing rich exotic physical phenomena, including anomalous Hall effect, axion electrodynamics and Majorana fermions. However, these unusual effects typically require extreme experimental conditions such as ultralow temperature or sophisticate material growth fabrication. Recently, new intrinsic magnetic topological insulators were proposed in MnBi2Te4-family compounds - on which could be realized under much...
We report the realization of novel symmetry-protected Dirac fermions in a surface-doped two-dimensional (2D) semiconductor, black phosphorus. The widely tunable band gap phosphorus by surface Stark effect is employed to achieve surprisingly large inversion up ∼0.6 eV. High-resolution angle-resolved photoemission spectra directly reveal pair creation points and their movement along axis glide-mirror symmetry. Unlike graphene, point stable, as protected space-time symmetry, even presence...
Topological superconductors (TSCs) are unconventional with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for quantum computation. Despite their importance in both fundamental research applications, natural TSCs very rare. Here, combining state of art synchrotron laser-based angle-resolved photoemission spectroscopy, we investigated a stoichiometric transition metal dichalcogenide (TMD), 2M-WS2 temperature 8.8 K (the highest among...
We investigated Pt-induced nanowires on the Si(110) surface using scanning tunneling microscopy (STM) and angle-resolved photoemission. High resolution STM images show a well-ordered nanowire array of 1.6 nm width 2.7 separation. Angle-resolved photoemission reveals fully occupied one-dimensional (1D) bands with Rashba-type split dispersion. Local $dI/dV$ spectra further indicate well-confined 1D electron channels nanowires, whose density states characteristics are consistent band splitting....
Dirac-like dispersion in topological surface states is strongly perturbed by hybridization with valence-band for Bi${}_{2}$Te${}_{3}$-terminated surfaces, but remains preserved MnBi${}_{2}$Te${}_{4}$-terminated surfaces.
We investigate background charge fluctuation in a GaAs quantum dot device by measuring 1/f noise the single-electron tunneling current through dot. The is understood as fluctuations of confinement potential and barriers. estimated increases almost linearly with temperature, which consistent simple model noise. find that very slightly when electrons are injected into excited states
A large anomalous Hall effect (AHE) has been observed in ferromagnetic ${\mathrm{Fe}}_{3}{\mathrm{Sn}}_{2}$ with breathing kagome bilayers. To understand the underlying mechanism for this, we investigate electronic structure of by angle-resolved photoemission spectroscopy (ARPES). In particular, use both vacuum ultraviolet light (VUV) and soft x ray (SX), which allow surface-sensitive relatively bulk-sensitive measurements, respectively, distinguish bulk states from surface states, should be...
In the novel stoichiometric iron-based material RbEuFe$_{4}$As$_{4}$ superconductivity coexists with a peculiar long-range magnetic order of Eu 4f states. Using angle-resolved photoemission spectroscopy, we reveal complex three dimensional electronic structure and compare it density functional theory calculations. Multiple superconducting gaps were measured on various sheets Fermi surface. High resolution resonant spectroscopy reveals states deep into phase. Both absolute values anisotropy...
Abstract Aqueous zinc‐ion batteries (AZIBs) are a promising alternative to lithium‐ion batteries, boasting superior safety, eco‐friendliness, and cost‐effectiveness. Despite these advantages, performance issues such as irregular Zn deposition cathode material dissolution remain challenging. This study introduces an intrinsically anisotropic ion‐guiding hydrogel electrolyte (APHE) fabricated via double‐stabilization freezing strategy. The synergistic effect of structure high water affinity...
We investigate the electronic structure of 2H and 3R polytypes NbS$_2$. The Fermi surfaces measured by angle-resolved photoemission spectroscopy show a remarkable difference in size, reflecting significantly increased band filling 3R-Nb$_{1+x}$S$_2$ compared to 2H-NbS$_2$, which we attribute presence additional interstitial Nb act as electron donors. Thus find that stoichiometry, rather than stacking arrangement, is most important factor physical properties two phases. Our high resolution...
The spin-resolved electronic band structure of Au-induced metallic atomic wires on a vicinal silicon surface, Si(553), was investigated using spin- and angle-resolved photoelectron spectroscopy. We directly measured the spin polarization three partially filled one-dimensional bands, one-third-filled band, doublet nearly half-filled bands. For doublet, strong apparent observed near Fermi energy with minor out-of-plane component. This observation is consistent Rashba-type spin-orbit splitting...
A superlattice of strained Au-Si atomic wires is successfully fabricated on a Si surface. Au atoms are known to incorporate into the stepped Si(111) surface form wire array with both one-dimensional (1D) metallic and antiferromagnetic chains. At reduced density Au, we find regular in alternation pristine nanoterraces. Pristine nanoterraces impose strain neighboring wires, which modifies band structure chains magnetic property spin This an ultimate 1D version strained-layer semiconductors,...
Kinks near the Fermi level observed in angle-resolved photoemission spectroscopy (ARPES) have been widely accepted to represent electronic coupling collective excitations, but kinks at higher energies eluded a unified description. We identify mechanism leading such kink features by means of ARPES and tight-binding band calculations on $\ensuremath{\sigma}$ bands graphene, where anomalous as high $\ensuremath{\sim}4\text{ }\text{ }\mathrm{eV}$ were reported recently [Phys. Rev. Lett. 111,...
The dosing of layered materials with alkali metals has become a commonly used strategy in ARPES experiments. However, precisely what occurs under such conditions, both structurally and electronically, remained matter debate. Here we perform systematic study 1T-HfTe$_2$, prototypical semimetal the transition metal dichalcogenide family. By utilizing photon energy-dependent angle-resolved photoemission spectroscopy (ARPES), have investigated electronic structure this material as function...
In this paper, a novel silicon nanowire photodetector on flexible substrate is presented for replacing the function of photoreceptors in retina to restore vision blind. An extremely high surface-to-volume-ratio characteristic capable developing highly-sensitive photonic sensors. Therefore, can be used as stand-alone visual perception device without an external camera. The first fabricated rigid substrate, and then transferred fit curvature eyeball. Experimental results using show very...