Hyeon Woo Lee

The orbital Hall effect describes the generation of the orbital current flowing in a perpendicular direction to an external electric field, analogous to the spin Hall effect. As the orbital current carries the angular momentum as the spin current does, injection of the orbital current into a ferromagnet can result in torque on the magnetization, which provides a way to detect the orbital Hall effect. With this motivation, we examine the current-induced spin-orbit torques in various ferromagnet/h

Abstract Three‐electrode plasma jet system consisting of a perforated dielectric tube with two outer and one floating inner electrodes was developed and employed for tooth bleaching. Lowered gas breakdown voltage and increased discharge current were achieved by using the floating inner electrode. Optical emission spectra analysis showed that the rotational temperature of the second positive nitrogen bands was ≈290 K and vibrational temperature was ≈2 500 K, which means this plasma is in highly n

We study phase coherent transport in a single channel system using the scattering matrix approach. It is shown that identical vanishing of the transmission amplitude occurs generically in quasi-1D systems if the time reversal is a good symmetry. The transmission zeros naturally lead to abrupt phase changes (without any intrinsic energy scale) and in-phase resonances, providing insights to recent experiments on phase coherent transport through a quantum dot.

We study electron counting statistics of a disordered conductor in the low-temperature limit. We derive an expression for the distribution of charge transmitted over a finite time interval by using a result from the random-matrix theory. In the metallic regime, the peak of the distribution is Gaussian and shows negligible sample-to-sample variations. On the contrary, the tails of the distribution are neither Gaussian nor Poisson-like and exhibit strong sample-to-sample variations.

Recently, the interest in natural products for the treatment of cancer is increasing because they are the pre-screened candidates. In the present study, we demonstrate the therapeutic effect of celastrol, a triterpene extracted from the root bark of Chinese medicine on gastric cancer. The proliferation of AGS and YCC-2 cells were most sensitively decreased in six kinds of gastric cancer cell lines after the treatment with celastrol. Celastrol inhibited the cell migration and increased G1 arrest

Abstract Controlling magnetic states by a small current is essential for the next‐generation of energy‐efficient spintronic devices. However, it invariably requires considerable energy to change a magnetic ground state of intrinsically quantum nature governed by fundamental Hamiltonian, once stabilized below a phase‐transition temperature. Here, it is reported that, surprisingly, an in‐plane current can tune the magnetic state of the nanometer‐thin van der Waals ferromagnet Fe 3 GeTe 2 from a ha

Abstract One of the ultimate goals of spintronics is to realize an efficient electrical manipulation of spin for high-speed and low-power nanodevices. A core ingredient for achieving this goal is the relativistic interaction between the electron’s orbital motion and spin, but the properties of the orbital angular momentum itself have remained largely unexplored. However, recent theories and experiments have uncovered that electrons may acquire nonvanishing orbital angular momentum when an extern

A layered two-dimensional superconducting material 2H-NbSe 2 is used to build a van der Waals heterostructure, where a proximity-coupled superconducting order can be induced in the interfacing materials. Vertically stacked NbSe 2 –graphene–NbSe 2 is fabricated using van der Waals interlayer coupling, producing defect-free contacts with a high interfacial transparency. The atomically thin graphene layer allows the formation of a highly coherent proximity Josephson coupling between the two NbSe 2

Subharmonic Shapiro step structure has been observed in the current-voltage characteristics of 300\ifmmode\times\else\texttimes\fi{}300 Nb-Au-Nb superconducting arrays. This subharmonic structure does not appear in the current-voltage characteristics of individual junctions, but appears to reflect a unique dynamical mode of the coupled system. A qualitative model is proposed that attributes the structure to the dynamical response of quantized loops of flux that are created by the antisymmetric s

Electron properties of carbon nanotubes in a transverse magnetic field are studied using a model of a massless Dirac particle on a cylinder. The problem possesses supersymmetry which protects low-energy states and ensures stability of the metallic behavior in arbitrarily large fields. In metallic tubes we find suppression of the Fermi velocity at half-filling and enhancement of the density of states. In semiconducting tubes the energy gap is suppressed. These features qualitatively persist (alth

Highly accurate calculations are reported for properties of vinylidene (H2C═C:), specifically the position of its zero-point vibrational level relative to that of acetylene and its equilibrium structure and ground state rotational constants. The isomerization energy of vinylidene calculated at the HEAT-456QP level of theory is 43.53 ± 0.15 kcal mol(-1), in agreement with the previous best estimate, but associated with a much smaller uncertainty. In addition, the thermochemical calculations prese