We systematically investigated the electronic structure of full-Heusler alloys with valence electron counts per formula unit 24 by using first-principles calculation. found various semiconducting flat bands at bottom conduction band. In terms low toxicity and cost, we focused on Fe2TiSn Fe2TiSi. that they could possess high thermoelectric power ranging from -300 to -160 µV/K electron-carrier concentrations 1×1020 1×1021 cm-3 around room temperature. Our results also suggest Fe2TiSn1-xSix...

Abstract Recent progress in magnetic tunnel junctions (MTJs) with a perpendicular easy axis consisting of CoFeB and MgO stacking structures has shown that magnetization dynamics are induced due to voltage-controlled anisotropy (VCMA), which will potentially lead future low-power-consumption information technology. For manipulating magnetizations MTJs by applying voltage, it is necessary understand the coupled motion two (recording reference) layers. In this report, we focus on layers top an...

The origin of the magnetism ${\text{MnSi}}_{1.7}$ nanoparticles in Si is investigated using first-principles calculations: bulk and interface effects are considered. magnetic property expected to be affected by stoichiometry, strain, charge accumulation. Stoichiometry accumulation induce a ferromagnetic state, strain stabilizes state. Another factor, ${\text{MnSi}}_{1.7}/\text{Si}$ formation, seen as triggering ferromagnetism strongly localized at interface. These two mechanisms shown...

The annealing-temperature (700–900 °C) dependence of the ferromagnetism manganese-implanted silicon is investigated. In annealed samples, manganese-containing nanoparticles, whose mean size was found to get bigger with temperature, are formed and these samples show ferromagnetism. We obtain evidence that at 800–850 °C produce two kinds ferromagnets one them offers a coercivity as high 2500 Oe, suggesting possibility Si-based nanostructures stable origin ferromagnetisms also discussed in...

We demonstrate the improved power factor in full-Heusler Fe2VAl1−xSix thin films using precise composition-control with off-axis sputtering method. The valence electron concentration per atom was varied from 5.9 to 6.1 by manipulating target substrate distance addition changing composition, resulting an up 3.0 mW/K2 m off-stoichiometric composition of Fe1.93V1.05Al0.77Si0.24. had a polycrystalline structure average grain size 40–50 nm. cumulative lattice thermal conductivity calculation as...

Thermoelectric properties of a semiconducting silicide, $\mathrm{C}{\mathrm{a}}_{3}\mathrm{S}{\mathrm{i}}_{4}$, were investigated by first-principles calculations. The calculation results revealed that $\mathrm{C}{\mathrm{a}}_{3}\mathrm{S}{\mathrm{i}}_{4}$ has relatively low lattice thermal conductivity around $1.2\phantom{\rule{0.16em}{0ex}}\mathrm{W}{\mathrm{m}}^{\ensuremath{-}1}{\mathrm{K}}^{\ensuremath{-}1}$ at 800 K. Seebeck coefficients and the electrical conductivities evaluated using...

We investigated thermoelectric properties of full-Heusler type Fe2VAl thin films. In order to achieve high Seebeck coefficient (S) and low resistivity (ρ) with thermal conductivity (κ), we fabricated films a MgO seed layer annealed them at 800℃. The the annealing process transform into L21-ordered Heusler structure. show S 59.5 µV/K ρ 3.14 µV m together κ 4.43 W/m•K, which results in ZT as 0.079. considerably small compared one bulk samples may originate from an enhancement phonon scattering...

Thermal boundary resistance (TBR) was controlled by changing the Ge ratio in a MnSi1.7-based nanocomposite with SiGe to investigate effects of TBR on thermal transport. We demonstrated continuous reduction conductivity down 1.2 W/Km, which is less than minimum MnSi1.7, even granular structures: practical forms thermoelectric (TE) technologies. The between MnSi1.7 and estimated quantitatively multilayered structures be as high 5.6 × 10−9 m2 K/W detailed analysis suggests that 20%–30%...

In this study, various Fe-based thermoelectric full-Heusler thin films were fabricated on MgO substrates by a post-annealing process. It is clarified that crystal growth through the process prevented both an initial crystallization and lattice mismatch between substrate. One of materials, namely, Fe2TiAl, was almost epitaxially grown substrate from amorphous state owing to small less than 3%. The properties Fe2TiAl-based modulated changing material composition. We found they strongly depend...

Abstract Fe 2 TiSi full-Heusler thin films were synthesized with a homogeneous single-phase structure and the composition was controlled in wide range by deposition techniques. By detailed tuning of film composition, Seebeck coefficient reached −184 μ V K −1 , which is almost maximum for alloys, power factor 3.9 mW −2 m . The thermal conductivity 3.5 W first-principles calculations clarified that this small value may be due to alloy scatterings. Consequently, ZT 0.36 at room temperature...

We investigate ferromagnetism of two-dimensional Pd nanoparticle superlattice by a magnetoresistance measurement. Magnetoresistance increases at coercive field with hysteretic behavior, which is consistent the result magnetization-field curve. This indicates that electrically detected. From maximum change, conduction-electron polarization estimated to be ∼4%. The nanoparticles evolved without protective agents; therefore, origin in chemically prepared associated intrinsic characteristic...

We report a lowered lattice thermal conductivity in nm-scale MnSi1.7/Si multilayers which were fabricated by controlling diffusions of Mn and Si atoms. The thickness the constituent layers is 1.5–5.0 nm, comparable to phonon mean free path both MnSi1.7 Si. By applying above nanostructures, we reduced down half that bulk composite materials. obtained value 1.0 W/K m experimentally observed minimum MnSi1.7-based materials without any heavy element doping close conductivity. attribute...

The electronic structure and quantum-transport properties of Fe/Fe2VAl/Fe trilayers were investigated by using first-principles calculations. high-transmission area in k-space can be confined a semimetallic Fe2VAl layer. originates from the small Fermi surface Fe2VAl. Moreover, symmetry matching wave functions between leads space trilayer around level is significant factor regard to designing confined-k-space current-perpendicular-to-plane giant-magnetoresistance (CPP-GMR) device, which...

We calculated electron-phonon coupling factors and lattice thermal conductivity of FCC metals L12 type binary alloys (X3Y: X,Y = Cu, Ag, Au, Pt, Pd) by using first-principles calculations. The Ag- Au-based are much lower than that Pd- Pt-based because the low density states around Fermi level alloys. conductivities Pd-, other their heavy atomic mass Au force constants. also evaluated interfacial resistance a metal/insulator bilayer originated from non-equilibrium state between electrons...

The electrochemical reduction of CO 2 is a technology great environmental and economic interest as it provides promising solution for reducing the concentration with producing valuable chemical compounds. Cu its alloys have attracted much attention because their moderate binding energy to multi-carbon (C2+) products[1]. reactivity product selectivity reaction (CO RR) depend on interfacial structure nano-scale morphology catalyst well material composition. Especially gas diffusion electrodes...

Carbon capture and conversion technologies have been widely studied as promising approaches to solving the global warming problem. The of CO 2 carbon-based chemicals fuels by electrochemical reduction (CO RR) using renewable electricity is one attractive strategies achieve carbon neutrality. Among various products RR, multi-carbon (C 2+ ) such ethylene ethanol are essential with high energy density value-added. Various metals, alloys, metal oxides electrocatalysts for but copper (Cu) its...

Abstract Pancreatic cancer is among the deadliest of all solid malignances. The 5-year survival rate pancreatic remains below 5%, mainly due to a lack early detection and highly metastatic properties that make surgery impossible in most cases. Therefore, it urgent find effective systemic therapies treat this cancer. KRAS activated vast majority cases cancer; unfortunately, therapeutic attempts inhibit directly have been unsuccessful. Our previous studies showed inhibition cyclin-dependent...

Uniaxial strain effects on manganese in silicon are investigated using the first-principles calculations. Manganese doping is shown to enhance increase rate of vertical as a function lateral by ∼10%. The formation energy decreases 0.1 eV at 3.3%. magnetic moments remain 3µB being independent magnitude. These results found both substitutional and interstitial tetrahedral manganese. An analysis detailed calculation reveals that these properties realized impact uniaxial electronic states

Magnetism of single-walled carbon nanotubes (SWNTs) filled with Pd in pseudo one-dimension is investigated based on the electronic structure obtained using first-principle calculation. In addition, stability nanowire inside SWNT evaluated through calculation binding energy. The monostrand inter-atomic distance 2.49 Å, which shows ferromagnetism free-standing state, has ferromagnetic moment also armchair type SWNTs diameter lager than 6.9 Å although magnetic smaller that corresponding...

In magnetic tunnel junctions (MTJs) with perpendicular easy axes, the retention times for parallel and antiparallel states are different because of dipolar coupling reference layer (RL). To make symmetrical, we model three types MTJs that have single or synthetic ferrimagnetic (SyF) RLs stepped structures. Micromagnetic calculations performed on basis Landau-Lifshitz-Gilbert equation motion to evaluate stray fields from each design. A SyF structure a step bottom has smallest field 2 mT at...

We investigated the thermoelectric properties of a metal/semiconductor multilayer by using simple parabolic band model and two-temperature model. The enables not only reducing thermal conductivity but also enhancing power factor nonequilibrium state between electrons phonons created interface. Our results revealed that combining metal with low lattice semiconductor high can compensate for their weak points each other in properties, resulting remarkable enhancement figure merit.