Dual Higgs modes entangled into a soliton lattice in CuTe.

Recently discovered Higgs particle is a key element in the standard model of elementary particles and its analogue in materials, massive Higgs mode, has elucidated intriguing collective phenomena in a wide range of materials with spontaneous symmetry breaking such as antiferromagnets, cold atoms, superconductors, superfluids, and charge density waves (CDW). As a straightforward extension beyond the standard model, multiple Higgs particles have been considered theoretically but not yet for Higgs modes. Here, we report the real-space observations, which suggest two Higgs modes coupled together with a soliton lattice in a solid.

Synthesis of silver sulfide nanoparticles and their photodetector applications.

Silver sulfide nanoparticles (AgS NPs) are currently being explored as infrared active nanomaterials that can provide environmentally stable alternatives to heavy metals such as lead. In this paper, we describe the novel synthesis of AgS NPs by using a sonochemistry method and the fabrication of photodetector devices through the integration of AgS NPs atop a graphene sheet. We have also synthesized Li-doped AgS NPs that exhibited a significantly enhanced photodetector sensitivity their enhanced absorption ability in the UV-NIR region.

Exploratory factor analysis of fluoride removal efficiency associated with the chemical properties of geomaterials.

This study explored the chemical properties of geomaterials in relation with their fluoride removal efficiencies from water under acidic conditions. Two types each of as-received and engineered steel slags were tested, and their F removal efficiencies were compared with those of other common or commercially available acid spill response materials. The chemical properties of the geomaterials were analyzed by x-ray photoelectron spectroscopy to determine their surface elemental compositions and by Brunauer-Emmett-Teller analysis to determine their surface areas.

Sn/Be Sequentially co-doped Hematite Photoanodes for Enhanced Photoelectrochemical Water Oxidation: Effect of Be(2+) as co-dopant.

For ex-situ co-doping methods, sintering at high temperatures enables rapid diffusion of Sn(4+) and Be(2+) dopants into hematite (α-Fe2O3) lattices, without altering the nanorod morphology or damaging their crystallinity. Sn/Be co-doping results in a remarkable enhancement in photocurrent (1.7 mA/cm(2)) compared to pristine α-Fe2O3 (0.

Phase transition-induced band edge engineering of BiVO4 to split pure water under visible light.

Through phase transition-induced band edge engineering by dual doping with In and Mo, a new greenish BiVO4 (Bi1-XInXV1-XMoXO4) is developed that has a larger band gap energy than the usual yellow scheelite monoclinic BiVO4 as well as a higher (more negative) conduction band than H(+)/H2 potential [0 VRHE (reversible hydrogen electrode) at pH 7]. Hence, it can extract H2 from pure water by visible light-driven overall water splitting without using any sacrificial reagents. The density functional theory calculation indicates that In(3+)/Mo(6+) dual doping triggers partial phase transformation from pure monoclinic BiVO4 to a mixture of monoclinic BiVO4 and tetragonal BiVO4, which sequentially leads to unit cell volume growth, compressive lattice strain increase, conduction band edge uplift, and band gap widening.

Highly selective solar-driven methanol from CO2 by a photocatalyst/biocatalyst integrated system.

The successful development of a photocatalyst/biocatalyst integrated system that carries out selective methanol production from CO2 is reported herein. The fine-tuned system was derived from a judicious combination of graphene-based visible light active photocatalyst (CCG-IP) and sequentially coupled enzymes. The covalent attachment of isatin-porphyrin (IP) chromophore to chemically converted graphene (CCG) afforded newly developed CCG-IP photocatalyst for this research endeavor.

Unconventional pore and defect generation in molybdenum disulfide: application in high-rate lithium-ion batteries and the hydrogen evolution reaction.

A 2H-MoS2 (H=hexagonal) ultrathin nanomesh with high defect generation and large porosity is demonstrated to improving electrochemical performance, including in lithium-ion batteries (LIBs) and the hydrogen evolution reaction (HER), with the aid of a 3D reduced graphene oxide (RGO) scaffold as fast electron and ion channels. The 3D defect-rich MoS2 nanomesh/RGO foam (Dr-MoS2 Nm/RGO) can be easily obtained through a one-pot cobalt acetate/graphene oxide (GO) co-assisted hydrothermal reaction, in which GO, cobalt and acetate ions are co-morphology-controlling agents and defect inducers. As an anode material for LIBs, Dr-MoS2 Nm/RGO has only a 9% capacity decay at a 10 C discharge rate versus 0.

Drawing circuits with carbon nanotubes: scratch-induced graphoepitaxial growth of carbon nanotubes on amorphous silicon oxide substrates.

Controlling the orientations of nanomaterials on arbitrary substrates is crucial for the development of practical applications based on such materials. The aligned epitaxial growth of single-walled carbon nanotubes (SWNTs) on specific crystallographic planes in single crystalline sapphire or quartz has been demonstrated; however, these substrates are unsuitable for large scale electronic device applications and tend to be quite expensive. Here, we report a scalable method based on graphoepitaxy for the aligned growth of SWNTs on conventional SiO₂/Si substrates.

Thermoelectric imaging of structural disorder in epitaxial graphene.

Heat is a familiar form of energy transported from a hot side to a colder side of an object, but not a notion associated with microscopic measurements of electronic properties. A temperature difference within a material causes charge carriers, electrons or holes to diffuse along the temperature gradient inducing a thermoelectric voltage. Here we show that local thermoelectric measurements can yield high-sensitivity imaging of structural disorder on the atomic and nanometre scales.

Structurally and electronically designed TiO₂Nx nanofibers for lithium rechargeable batteries.

The morphology and electronic structure of metal oxides, including TiO(2) on the nanoscale, definitely determine their electronic or electrochemical properties, especially those relevant to application in energy devices. For this purpose, a concept for controlling the morphology and electrical conductivity in TiO(2), based on tuning by electrospinning, is proposed. We found that the 1D TiO(2) nanofibers surprisingly gave higher cyclic retention than 0D nanopowder, and nitrogen doping in the form of TiO(2)N(x) also caused further improvement.

Photoconductivity and enhanced memory effects in hybrid C60-graphene transistors.

We describe the observation of photoconductivity and enhanced memory effects in graphene devices functionalized with clusters of alkylated C(60) molecules. The alkylated C(60) clusters were adsorbed on chemical vapor deposition-grown graphene devices from an aprotic medium. The resulting alkylated C(60)-graphene hybrid devices showed reproducible photoconductive behavior originating from the electron-accepting nature of the C(60) molecules.

A photocatalyst-enzyme coupled artificial photosynthesis system for solar energy in production of formic acid from CO2.

The photocatalyst-enzyme coupled system for artificial photosynthesis process is one of the most promising methods of solar energy conversion for the synthesis of organic chemicals or fuel. Here we report the synthesis of a novel graphene-based visible light active photocatalyst which covalently bonded the chromophore, such as multianthraquinone substituted porphyrin with the chemically converted graphene as a photocatalyst of the artificial photosynthesis system for an efficient photosynthetic production of formic acid from CO(2). The results not only show a benchmark example of the graphene-based material used as a photocatalyst in general artificial photosynthesis but also the benchmark example of the selective production system of solar chemicals/solar fuel directly from CO(2).

Resolving microscopic interfaces in Si(1-x)Ge(x) alloy nanowire devices.

We have fabricated Si(1-x)Ge(x) alloy nanowire devices with Ni and Ni/Au electrodes. The electrical transport characteristics of the alloy nanowires depended strongly on the annealing temperature and contact metals. Ni/Au-contacted devices annealed at 400 degrees C showed p-type transistor behavior as well as a resistance switching effect, while no switching was observed from Ni-contacted alloy nanowire devices.

Detection of tumor markers using single-walled carbon nanotube field effect transistors.

We have developed a biosensor capable of detecting carcinoembryonic antigen (CEA) markers using single-walled carbon nanotube field effect transistors (SWNT-FETs). These SWNT-FETs were fabricated using nanotubes produced by a patterned catalyst growth technique, where the top contact electrodes were generated using conventional photolithography. For biosensor applications, SU-8 negative photoresist patterns were used as an insulation layer.

First-principles studies of SnS2 nanotubes: a potential semiconductor nanowire.

First principles calculations are used to predict the stability and electronic structures of SnS(2) nanotubes. Optimization of several structures and their corresponding strain energies confirm the stability of SnS(2) nanotube structures. Band structure calculations show that SnS(2) nanotubes could have moderate band gaps regardless of their chirality.