Room-Temperature Synthesis of Carbon Nanochains via the Wurtz Reaction.

In the field of surface synthesis, various reactions driven by the catalytic effect of metal substrates, particularly the Ullmann reaction, have been thoroughly investigated. The Wurtz reaction facilitates the coupling of alkyl halides through the removal of halogen atoms with a low energy barrier on the surface; however, the preparation of novel carbon nanostructures via the Wurtz reaction has been scarcely reported. Here, we report the successful synthesis of ethyl-bridged binaphthyl molecular chains on Ag(111) at room temperature via the Wurtz reaction.

Thermal biasing for lattice symmetry breaking and topological edge state imaging.

Marginally twisted bilayer graphene with large Bernal stacked domains involves symmetry-breaking features with domain boundaries that exhibit topological edge states normally obscured by trivial bands. A vertical electric field can activate these edge states through inversion symmetry breaking and opening a bandgap around the edge state energy. However, harnessing pristine topological states at the Fermi level without violent electric or magnetic bias remains challenging, particularly above room temperature.

On-surface synthesis of aromatic cyclo[10]carbon and cyclo[14]carbon.

All-carbon materials based on sp-hybridized atoms, such as fullerenes, carbon nanotubes and graphene, have been much explored due to their remarkable physicochemical properties and potential for applications. Another unusual all-carbon allotrope family are the cyclo[n]carbons (C) consisting of two-coordinated sp-hybridized atoms. They have been studied in the gas phase since the twentieth century, but their high reactivity has meant that condensed-phase synthesis and real-space characterization have been challenging, leaving their exact molecular structure open to debate.

Bottom-Up Synthesis of Metalated Carbyne Ribbons via Elimination Reactions.

Elimination reactions are one of the most important reactions in organic synthesis, especially in the formation of alkenes and alkynes. Herein, based on scanning tunneling microscopy, we report the bottom-up synthesis of one-dimensional carbyne-like nanostructures, metalated carbyne ribbons with the incorporation of Cu or Ag atoms, through α- and β-elimination reactions of tetrabromomethane and hexabromoethane on surfaces. Density functional theory calculations demonstrate a width-dependent band gap modulation within these ribbon structures, which is affected by interchain interactions.

Atomic-scale thermopower in charge density wave states.

The microscopic origins of thermopower have been investigated to design efficient thermoelectric devices, but strongly correlated quantum states such as charge density waves and Mott insulating phase remain to be explored for atomic-scale thermopower engineering. Here, we report on thermopower and phonon puddles in the charge density wave states in 1T-TaS, probed by scanning thermoelectric microscopy. The Star-of-David clusters of atoms in 1T-TaS exhibit counterintuitive variations in thermopower with broken three-fold symmetry at the atomic scale, originating from the localized nature of valence electrons and their interlayer coupling in the Mott insulating charge density waves phase of 1T-TaS.

Quantum Sensing of Thermoelectric Power in Low-Dimensional Materials.

Thermoelectric power, has been extensively studied in low-dimensional materials where quantum confinement and spin textures can largely modulate thermopower generation. In addition to classical and macroscopic values, thermopower also varies locally over a wide range of length scales, and is fundamentally linked to electron wave functions and phonon propagation. Various experimental methods for the quantum sensing of localized thermopower have been suggested, particularly based on scanning probe microscopy.

Robust Quantum Oscillation of Dirac Fermions in a Single-Defect Resonant Transistor.

The massless nature of Dirac Fermions produces large energy gaps between Landau levels (LLs), which is promising for topological devices. While the energy gap between the zeroth and first LLs reaches 36 meV in a magnetic field of 1 T in graphene, exploiting the quantum Hall effect at room temperature requires large magnetic fields (∼30 T) to overcome the energy level broadening induced by charge inhomogeneities in the device. Here, we report a way to use the robust quantum oscillations of Dirac Fermions in a single-defect resonant transistor, which is based on local tunneling through a thin (∼1.

Harnessing Thermoelectric Puddles the Stacking Order and Electronic Screening in Graphene.

Thermoelectricity has been investigated mostly on the macroscopic scale despite the fact that its origin is linked to the local electronic band structure of materials. While the role of thermopower from microscopic structures (, surfaces or grain boundaries) increases for emerging thermoelectric materials, manipulating thermoelectric puddles, spatially varying levels of thermoelectric power on the nanometer scale, remains unexplored. Here, we illustrate thermoelectric puddles that can be harnessed the stacking order and electronic screening in graphene.

Resonant Tunneling Spectroscopy to Probe the Giant Stark Effect in Atomically Thin Materials.

Each atomic layer in van der Waals heterostructures possesses a distinct electronic band structure that can be manipulated for unique device operations. In the precise device architecture, the subtle but critical band splits by the giant Stark effect between atomic layers, varied by the momentum of electrons and external electric fields in device operation, has not yet been demonstrated or applied to design original devices with the full potential of atomically thin materials. Here, resonant tunneling spectroscopy based on the negligible quantum capacitance of 2D semiconductors in resonant tunneling transistors is reported.

Coherent Thermoelectric Power from Graphene Quantum Dots.

The quantum confinement of charge carriers has been a promising approach to enhance the efficiency of thermoelectric devices, by lowering the dimension of materials and raising the boundary phonon scattering rate. The role of quantum confinement in thermoelectric efficiency has been investigated by using macroscopic device-scale measurements based on diffusive electron transport with the thermal de Broglie wavelength of the electrons. Here, we report a new class of thermoelectric operation originating from quasi-bound state electrons in low-dimensional materials.

Sub-molecular spectroscopy and temporary molecular charging of Ni-phthalocyanine on graphene with STM.

In this study, the self-assembled molecular network and electronic properties of Ni-phthalocyanine (NiPc) molecules on monolayer graphene (MLG)/6H-SiC(0001) were studied by room temperature Scanning Tunnelling Microscopy (STM) and Density Functional Theory (DFT) calculations. In this study, a very weak electronic coupling between the graphene and the NiPc molecules is found. This is due to the very small charge transfer of only 0.

[Present application situation of medical consumble materials and the standard management].

This paper introduces the present application situation of medical consumable materials in consumption, use, quality control and computer management. It presents the concrete contents of standard management in quality guarantee, rules and regulations, and cost reduction.