Hosik Lee

To understand the formation mechanism of magnetic moments at the edges of graphitic fragments, we carry out first-principles density-functional calculations for the electronic and magnetic structures of graphitic fragments with various spin and geometric configurations. We find that interedge and interlayer interactions between the localized moments can be explained in terms of interactions between the magnetic tails of the edge-localized states. In addition, the dihydrogenated edge states as we

A fast-charging battery that supplies maximum energy is a key element for vehicle electrification. High-capacity silicon anodes offer a viable alternative to carbonaceous materials, but they are vulnerable to fracture due to large volumetric changes during charge-discharge cycles. The low ionic and electronic transport across the silicon particles limits the charging rate of batteries. Here, as a three-in-one solution for the above issues, we show that small amounts of sulfur doping (<1 at%) ren

A non-vanishing electric field inside a non-centrosymmetric crystal transforms into a momentum-dependent magnetic field, namely, a spin–orbit field (SOF). SOFs are of great use in spintronics because they enable spin manipulation via the electric field. At the same time, however, spintronic applications are severely limited by the SOF, as electrons traversing the SOF easily lose their spin information. Here, we propose that in-plane ferroelectricity in (001)-oriented SnTe thin films can support

Good cyclability is essential for the potential application of cathode materials. Here, we investigate the structural stability of two-dimensional (2D) Li-layered and three-dimensional (3D) structured polymorphs of Li2FeSiO4 and Li2MnSiO4 using the density functional theory calculations. We find that all 2D Li-layered polymorphs of both materials are unstable upon full delithiation owing to layer exfoliation, which can lead to an amorphous structure. However, in contrast to the fact that the amo

We performed first-principles calculations to investigate the magnetic, mechanical and electronic properties of the tetrachalcogenide CrPS₄. Although bulk CrPS₄ has been shown to exhibit a low-dimensional antiferromagnetic (AFM) ground state where ferromagnetic (FM) Cr-chains are coupled antiferromagnetically, our calculations indicated that the monolayer can be transformed to an FM material by applying a uniaxial tensile strain of ⩾4% along the FM Cr-chain direction. The A

Anion exchange membrane water electrolysis (AEMWE) is attracting attention as a next-generation technology for producing hydrogen from water. To maximize the efficiency of AEMWE systems, electrodes fabricated using nonprecious metal catalysts that possess high activity and durability are required to make the AEMWE system operable in alkaline environments. In this study, we investigate the effect of Ti impurities on the oxygen evolution reaction (OER) kinetics of NiFe2O4 (NFO). Ti impurities can

Heavy metal contamination from abandoned mine areas is a major threat for the environment. The study objective was to categorize the most polluted mine areas among 44 mine sites at the four cities of Chungcheongbuk-do province in South Korea. Both water and soil samples were collected from the mine area. The pH of the water and soil ranged from 3.6 to 8.5 and from 4.1 to 9.1 respectively. A significant amount of arsenic (As), cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn) and mercu

Electrochemical carbon dioxide reduction is a mild and eco-friendly approach for CO₂ mitigation and producing value-added products. For selective electrochemical CO₂ reduction, single-crystalline Au particles (octahedron, truncated-octahedron, and sphere) are synthesized by consecutive growth and chemical etching using a polydiallyldimethylammonium chloride (polyDDA) surfactant, and are surface-functionalized. Monodisperse, single-crystalline Au nanoparticles provide an ide

We investigated possible sources of defect-induced magnetic ordering in carbon-irradiated graphite from first-principles calculations. Among candidate structures with interstitial defect configurations that could be generated during carbon irradiation processes, two metastable configurations with finite magnetic moments were identified. They are coupled ferromagnetically to their neighboring defects, thereby enabling them to contribute to the observed macroscopic magnetic ordering. The Ruderman-

The laser flash photolysis process of diazomethane has been studied by using a real time propagation time-dependent density functional theory (RTP-TDDFT) combined with molecular dynamics. The activation energy barrier for disintegrating diazomethane into nitrogen (N(2)) and carbene (CH(2)) molecules significantly decreases in the electronic excited S(1) state compared to that in the S(0) ground state. Furthermore, the produced carbene molecule can be in the electronic excited state of (1)CH(2) (

Abstract Understanding the atomic mechanism of low‐temperature CO oxidation on a heterogeneous catalyst is challenging. We performed density functional theory (DFT) calculations to identify the surface structure and reaction mechanism responsible for low‐temperature CO oxidation on Pd/CeO 2 (100) surfaces. DFT calculations reveal the formation of a unique zigzag chain structure by the oxygen and Ce atoms of the topmost surface of CeO 2 (100) with Pd atoms located between the zigzag chains. O 2 a