Boosting Thermoelectric Performance in Epitaxial GeTe Film/Si by Domain Engineering and Point Defect Control.

This study demonstrates a simultaneous realization of ultralow thermal conductivity and high thermoelectric power factor in epitaxial GeTe thin films/Si substrates by a combination of the interface introduction by domain engineering and the suppression of Ge vacancy generation by point defect control. We formed epitaxial Te-poor GeTe thin films having low-angle grain boundaries with a misorientation angle close to 0° or twin interfaces with a misorientation angle close to 180°. The control of interfaces and point defects gave rise to ultralow lattice thermal conductivity of ∼0.

Curcumin tautomerization in the mechanism of pentameric amyloid- β42 oligomers disassembly.

Alzheimer's disease is a neurologic disorder characterized by the accumulation of extracellular deposits of amyloid-β (Aβ) fibrils in the brain of patients. The key etiologic agent in Alzheimer's disease is not known; however oligomeric Aβ appears detrimental to neuronal functions and increases Aβ fibrils deposition. Previous research has shown that curcumin, a phenolic pigment of turmeric, has an effect on Aβ assemblies, although the mechanism remains unclear.

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO engineering.

Vanadium dioxide (VO) material, known for changing physical properties due to metal-insulator transition (MIT) near room temperature, has been reported to undergo a phase change depending on the strain. This fact can be a significant problem for nanoscale devices in VO, where the strain field covers a large area fraction, spatially non-uniform, and the amount of strain can vary during the MIT process. Direct measurement of the strain field distribution during MIT is expected to establish a methodology for material phase identification.

The Effect of Ethanol on Disassembly of Amyloid-β Pentamer Revealed by Atomic Force Microscopy and Gel Electrophoresis.

The most common type of dementia, Alzheimer's disease, is associated with senile plaques formed by the filamentous aggregation of hydrophobic amyloid-β (Aβ) in the brains of patients. Small oligomeric assemblies also occur and drugs and chemical compounds that can interact with such assemblies have attracted much attention. However, these compounds need to be solubilized in appropriate solvents, such as ethanol, which may also destabilize their protein structures.

Phonon transport in the nano-system of Si and SiGe films with Ge nanodots and approach to ultralow thermal conductivity.

Phonon transport in the nano-system has been studied using well-designed nanostructured materials to observe and control the interesting phonon behaviors like ballistic phonon transport. Recently, we observed drastic thermal conductivity reduction in the films containing well-controlled nanodots. Here, we investigate whether this comes from the interference effect in ballistic phonon transport by comparing the thermal properties of the Si or Si0.

A Chiral Metal-Organic 1D-Coordination Polymer Upon Complexation of Phenylene-Bridged Bipyrrole and Palladium (II) Ion.

Metal-organic 1D-coordination polymers, having unique electronic and optical properties, are expected to be a novel advanced functional material capable of fabricating smart plastics, films, and fibers. In this study, we have synthesized a novel metal-organic 1D-coordination polymer composed of a phenylene-bridged bipyrrole bearing -alkylimino groups (BPI) and palladium(II) ion. The BPI and Pd(II) form square planar bis(bidentate) complex to form a metal coordinated π-conjugation polymer (Poly-BPI/Pd).

High Thermoelectric Power Factor Realization in Si-Rich SiGe/Si Superlattices by Super-Controlled Interfaces.

A Si-based superlattice is one of the promising thermoelectric films for realizing a stand-alone single-chip power supply. Unlike a p-type superlattice (SL) achieving a higher power factor due to strain-induced high hole mobility, in the n-type SL, the strain can degrade the power factor due to lifting conduction band degeneracy. Here, we propose epitaxial Si-rich SiGe/Si SLs with ultrathin Ge segregation interface layers.

Resistive switching memory performance in oxide hetero-nanocrystals with well-controlled interfaces.

For realization of new informative systems, the memristor working like synapse has drawn much attention. We developed isolated high-density FeO nanocrystals on Ge nuclei/Si with uniform and high resistive switching performance using low-temperature growth. The FeO nanocrystals on Ge nuclei had a well-controlled interface (FeO/GeO/Ge) composed of high-crystallinity FeO and high-quality GeO layers.

Methodology of Thermoelectric Power Factor Enhancement by Controlling Nanowire Interface.

The simultaneous realization of low thermal conductivity and high thermoelectric power factor in materials has long been the goal for the social use of high-performance thermoelectric modules. Nanostructuring approaches have drawn considerable attention because of the success in reducing thermal conductivity. On the contrary, enhancement of the thermoelectric power factor, namely, the simultaneous increase of the Seebeck coefficient and electrical conductivity, has been difficult.

Response analysis for identifying the origin of photo-modulated current contrasts in scanning tunneling microscopic imaging semiconductor surfaces.

Inhomogeneities in semiconductor solids can be imaged by two-dimensional mapping of the amplitude of periodically modulated tip current in scanning tunneling microscopy that is induced by illumination of semiconductor samples with a chopped light. It has been shown that it is possible to distinguish between plural origins of the photo-modulated current by analyzing the response properties of the current signal. A judicial choice of the modulation frequency is important for the required contrasts to be obtained.