Preceding the current interest in layered materials for electronic applications, research 1960's found that black phosphorus combines high carrier mobility with a fundamental band gap. We introduce its counterpart, dubbed few-layer phosphorene, as new 2D p-type material. Same graphene and MoS2, phosphorene is flexible can be mechanically exfoliated. find to stable and, unlike graphene, have an inherent, direct appreciable band-gap depends on number of layers. Our transport studies indicate...

Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation a laser-vaporized carbon-nickel-cobalt mixture at 1200degreesC. X-ray diffraction and electron microscopy showed that these SWNTs are nearly uniform diameter they self-organize into "ropes," which consist 100 to 500 two-dimensional triangular lattice with constant 17 angstroms. The x-ray form factor is consistent uniformly charged cylinders 13.8 +/- 0.2 angstroms diameter. ropes metallic,...

Combining equilibrium and nonequilibrium molecular dynamics simulations with accurate carbon potentials, we determine the thermal conductivity lambda of nanotubes its dependence on temperature. Our results suggest an unusually high value, approximately 6600 W/m K, for isolated (10,10) nanotube at room temperature, comparable to a hypothetical graphene monolayer or diamond. that these values are associated large phonon mean free paths in systems; substantially lower predicted observed basal...

Field emission of electrons from individually mounted carbon nanotubes has been found to be dramatically enhanced when the nanotube tips are opened by laser evaporation or oxidative etching. Emission currents 0.1 1 microampere were readily obtained at room temperature with bias voltages less than 80 volts. The emitting structures concluded linear chains atoms, C n , ( = 10 100), pulled out open edges graphene wall layers force electric field, in a process that resembles unraveling sleeve sweater.

We investigate a previously unknown phase of phosphorus that shares its layered structure and high stability with the black allotrope. find in-plane hexagonal bulk layer stacking this structure, which we call "blue phosphorus," to be related graphite. Unlike graphite phosphorus, blue displays wide fundamental band gap. Still, it should exfoliate easily form quasi-two-dimensional structures suitable for electronic applications. study likely transformation pathway from discuss possible ways...

Based on ab initio density functional calculations, we propose $\ensuremath{\gamma}\text{\ensuremath{-}}\mathrm{P}$ and $\ensuremath{\delta}\text{\ensuremath{-}}\mathrm{P}$ as two additional stable structural phases of layered phosphorus besides the $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{P}$ (black) $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{P}$ (blue) allotropes. Monolayers some these allotropes have a wide band gap, whereas others, including...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-Assembly of Tubular FullerenesTing Guo, Pavel Nikolaev, Andrew G. Rinzler, David Tomanek, Daniel T. Colbert, and Richard E. SmalleyCite this: J. Phys. Chem. 1995, 99, 27, 10694–10697Publication Date (Print):July 1, 1995Publication History Published online1 May 2002Published inissue 1 July 1995https://pubs.acs.org/doi/10.1021/j100027a002https://doi.org/10.1021/j100027a002research-articleACS PublicationsRequest reuse permissionsArticle...

Studying the reason why single-layer molybdenum disulfide (${\mathrm{MoS}}_{2}$) appears to fall short of its promising potential in flexible nanoelectronics, we find that nature contacts plays a more important role than semiconductor itself. In order understand ${\mathrm{MoS}}_{2}/\mathrm{metal}$ contacts, perform ab initio density functional theory calculations for geometry, bonding, and electronic structure contact region. We most common metal (Au) is rather inefficient electron injection...

We propose that superconductivity in ${\mathit{A}}_{3}$${\mathrm{C}}_{60}$ (A=K, Rb) with ${\mathit{T}}_{\mathit{c}}$\ensuremath{\ge}30 K results from a favorable combination of high phonon frequencies and the existence two different energy scales optimizing coupling constant \ensuremath{\lambda}=NV. Calculations show electron scattering V is dominated by particular on-ball Jahn-Teller-type modes on scale large \ensuremath{\pi}-hopping energy, while density states N controlled weak interball...

We report the fabrication of both n-type and p-type WSe2 field effect transistors with hexagonal boron nitride passivated channels ionic-liquid (IL)-gated graphene contacts. Our transport measurements reveal intrinsic channel properties including a metal-insulator transition at characteristic conductivity close to quantum conductance e2/h, high ON/OFF ratio >107 170 K, large electron hole mobility ~200 cm2V-1s-1 160 K. Decreasing temperature 77 K increases electrons ~330 that holes ~270...

We report a new strategy for fabricating 2D/2D low-resistance ohmic contacts variety of transition metal dichalcogenides (TMDs) using van der Waals assembly substitutionally doped TMDs as drain/source and with no intentional doping channel materials. demonstrate that few-layer WSe2 field-effect transistors (FETs) exhibit low contact resistances ∼0.3 kΩ μm, high on/off ratios up to >10(9), drive currents exceeding 320 μA μm(-1). These favorable characteristics are combined two-terminal hole...

A simple theory is presented for various fundamental properties of small clusters. In particular, we calculate the cohesion, magic numbers, bond contraction, stability atomic structures, and alloy formation as a function cluster size, determine also Coulomb explosion multiply charged

We report the fabrication of ionic liquid (IL) gated field-effect transistors (FETs) consisting bilayer and few-layer MoS2. Our transport measurements indicate that electron mobility about 60 cm2V-1s-1 at 250 K in devices exceeds significantly comparable back-gated devices. IL-FETs display a increase from 100 180 to 220 77 good agreement with true channel determined four-terminal measurements, ambipolar behavior high ON/OFF ratio >107 (104) for electrons (holes), near ideal sub-threshold...

We investigate spin conductance in zigzag graphene nanoribbons and propose a injection mechanism based only on graphitic nanostructures. find that with atomically straight, symmetric edges show zero but nonzero Hall conductance. Only asymmetrically shaped give rise to finite can be used for into graphene. Furthermore, rough exhibit mesoscopic fluctuations universal value of $\mathrm{rms}{G}_{s}\ensuremath{\approx}0.4e/4\ensuremath{\pi}$.

An outstanding challenge of theoretical electronic structure is the description van der Waals (vdW) interactions in molecules and solids. Renewed interest resolving this part motivated by technological promise layered systems including graphite, transition metal dichalcogenides, more recently, black phosphorus, which interlayer interaction widely believed to be dominated these types forces. We report a series quantum Monte Carlo (QMC) calculations for bulk phosphorus related few-layer...

Abstract Despite extensive research for more than 200 years, the experimental isolation of monatomic sulphur chains, which are believed to exhibit a conducting character, has eluded scientists. Here we report synthesis previously unobserved composite material elemental sulphur, consisting chains stabilized in constraining volume carbon nanotube. This one-dimensional phase is confirmed by high-resolution transmission electron microscopy and synchrotron X-ray diffraction. Interestingly, these...

Abstract Electron–electron and electron–phonon interactions are two major driving forces that stabilize various charge-ordered phases of matter. In layered compound 1T-TaS 2 , the intricate interplay between generates a Mott-insulating ground state with peculiar charge-density-wave (CDW) order. The delicate balance also makes it possible to use external perturbations create manipulate novel in this material. Here, we study mosaic CDW phase induced by voltage pulses, find new exhibits...

We study the equilibrium geometry and electronic structure of thin films layered gray arsenic using ab initio density functional theory. In contrast to bulk As that is semimetallic, display a significant band gap depends sensitively on number layers, in-layer strain, layer stacking, interlayer spacing. find metallic character can be introduced by increasing layers beyond two or subjecting semiconducting monolayers bilayers moderate tensile strain. The strain-induced metal-semiconductor...

We have measured the Raman spectrum of individual single walled carbon nanotubes in solution and compare it to that obtained from same starting material where tubes are present ordered bundles or ropes. Interestingly, radial mode frequencies for found be $\ensuremath{\sim}10\mathrm{cm}{}^{\ensuremath{-}1}$ higher than those observed a rope, apparent contradiction lattice dynamics predictions. suggest there is no such contradiction, propose upshift due rather decreased energy spacing Van Hove...

Chemical modification by SOCl2 of an entangled network purified single-wall carbon nanotubes, also known as 'bucky paper', is reported to profoundly change the electrical and mechanical properties this system. Four-probe measurements indicate a conductivity increase up factor 5 at room temperature even more pronounced lower temperatures. This chemical improves SWNT networks. Whereas pristine sample shows overall semiconducting character, modified material behaves metal. The effect studied in...

We propose a catalytic growth mechanism of single-wall carbon nanotubes based on density functional total energy calculations. Our results indicate with an ``armchair'' edge to be energetically favored over ``zigzag'' nanotubes. also suggest that highly mobile Ni catalyst atoms adsorb at the growing nanotube, where they catalyze continuing assembly hexagons from feedstock diffusing along nanotube wall. In concerted exchange mechanism, anneal pentagons would initiate dome closure nanotube.

The electromagnetic response function of a ${\mathrm{C}}_{60}$ cluster is calculated using linear-response theory. We find that the valence electrons are quite delocalized and show collective excitations. In low-energy part excitation spectrum, lowest allowed transition at \ensuremath{\Elzxh}\ensuremath{\omega}\ensuremath{\approxeq}3 eV strongly screened, other transitions below 6 moderately in agreement with experiment. also predict giant resonance an unusually high energy...

Images of the (0001) surface graphite observed in scanning-tunneling microscope (STM) show a strong asymmetry tunneling current between neighboring carbon atoms hexagonal ring. The magnitude this is seen to be almost independent polarity and decrease slightly with increasing amplitude bais voltage for voltages below 1 V. A theory developed that explains anomaly as purely electronic effect, arising from symmetry states scanned by STM, which dominates over topography graphite. predicted trends...