Fractional Quantum Hall Effect from Frustration-Free Hamiltonians.

We show that there is an emergent lattice description for the continuous fractional quantum Hall (FQH) systems, with a generalized set of few-body coherent states. In particular, model Hamiltonians of the FQH effect (FQHE) are equivalent to the real-space von Neumann lattice of local projection operators imposed on a continuous system in the thermodynamic limit. It can be analytically derived that tuning local one-body potentials in such lattices amounts to the tuning of individual two- or few-body pseudopotentials.

Evolution of intrinsic vacancies and prolonged lifetimes of vacancy clusters in black phosphorene.

Due to the relatively low formation energies and highly mobile characteristics of atomic vacancies in phosphorene, understanding their evolution becomes crucial for its structural integrity, chemical activities and applications. Herein, by combining first-principles calculations and kinetic Monte Carlo simulation, we investigate the time evolution and formation of atomic vacancy clusters from isolated monovacancies (MVs), aiming to uncover the mechanisms of diffusion, annihilation, and reaction of these atomic vacancies. We find that while isolated MVs possess a highly mobile characteristic, they react and form MV pairs which possess much lower mobility and high stability under ambient conditions.

The mechanical and thermal properties of MoS-WSe lateral heterostructures.

The recently fabricated monolayer MoS2-WSe2 lateral heterostructures are promising for many interesting applications, such as p-n diodes, photodetectors, transistors, sensors, light-emitting diodes and thermoelectric and flexible nanodevices. In this work, we study the mechanical and thermal properties of MoS2-WSe2 lateral heterostructures by using molecular dynamics (MD) simulations based on the recently parameterized Stillinger-Weber (SW) potential. It is found that the fracture strength and fracture strain of MoS2-WSe2 lateral heterostructures are dictated by the mechanical properties of MoS2, and are very sensitive to temperature.

Ultrahigh binding affinity of a hydrocarbon guest inside cucurbit[7]uril enhanced by strong host-guest charge matching.

Cucurbit[7]uril (CB[7]) is an artificial macrocyclic molecule that can form exceptionally strong host-guest complexes with binding constants higher than that of the biotin-avidin complex. Despite notable experimental efforts, there do not exist large-scale computational investigations on finding strongly binding guests of CB[7]. Herein, we develop a computational approach based on large-scale molecular modelling to predict strongly binding hydrocarbon motifs.

A Monte Carlo model for self-assembly of polytetrafluoroethylene nanoparticle films via repulsive electrostatic interactions.

Self-assembly of polytetrafluoroethylene (PTFE) nanoparticle films on an aluminum alloy substrate under repulsive electrostatic interactions has been achieved experimentally. However, a theoretical framework which is able to accurately predict the self-assembly kinetics based on their underlying mechanisms is not yet available. In this work, we formulate a Monte Carlo model to make predictions on the formation of close-packed monolayer and multilayer PTFE nanoparticle films during repulsive electrostatic self-assembly.

Nature of halogen bonding involving π-systems, nitroxide radicals and carbenes: a highlight of the importance of charge transfer.

The recently developed adiabatic absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) has proven to be useful in determining the effects of different energy components on the geometries of complexes bound by intermolecular interactions. The authors have applied it to systems such as the water dimer, water-ion complexes, metallocenes and lone-pair type halogen-bonded (XB) dimers. In this study, we have extended the second-generation ALMO-EDA method to 40 different XB complexes by benchmarking against its classical counterpart and symmetry-adapted perturbation theory (SAPT).

MoS/ZnO van der Waals heterostructure as a high-efficiency water splitting photocatalyst: a first-principles study.

Previous investigations [H. L. Zhuang and R.

Exploring the charge localization and band gap opening of borophene: a first-principles study.

Recently synthesized two-dimensional (2D) boron, borophene, exhibits a novel metallic behavior rooted in the s-p orbital hybridization, distinctively different from other 2D materials such as sulfides/selenides and semi-metallic graphene. This unique feature of borophene implies new routes for charge delocalization and band gap opening. Herein, using first-principles calculations, we explore the routes to localize the carriers and open the band gap of borophene via chemical functionalization, ribbon construction, and defect engineering.

Size-dependent properties of transition metal clusters: from molecules to crystals and surfaces--computational studies with the program ParaGauss.

In the so-called scalable regime the size-dependent behavior of the physical and chemical properties of transition metal clusters is described by scaling relationships. For most quantities this scalable regime is reached for cluster sizes between a few tens and a few hundreds of atoms, hence for systems for which an accurate treatment by density functional theory is still feasible. Thus, by invoking scaling relations one is able to obtain properties of very large nanoparticles and even the bulk limit from the results of a series of smaller cluster models.

Wetting transition on patterned surfaces: transition states and energy barriers.

We study the wetting transition on microstructured hydrophobic surfaces. We use the string method [J. Chem.

A climbing string method for saddle point search.

The string method originally proposed for the computation of minimum energy paths (MEPs) is modified to find saddle points around a given minimum on a potential energy landscape using the location of this minimum as only input. In the modified method the string is evolved by gradient flow in path space, with one of its end points fixed at the minimum and the other end point (the climbing image) evolving towards a saddle point according to a modified potential force in which the component of the potential force in the tangent direction of the string is reversed. The use of a string allows us to monitor the evolution of the climbing image and prevent its escape from the basin of attraction of the minimum.

Measurements of dynamic forces between drops with the AFM: novel considerations in comparisons between experiment and theory.

Dynamic forces between a deformable tetradecane oil drop (radius of curvature ≈ 25 μm) anchored on the cantilever of the Atomic Force Microscope (AFM) and similar oil drops (radii of curvature 80 to 500 μm) on the substrate in aqueous electrolyte with added sodium dodecyl sulfate surfactant have been studied. Measurements were made over a range of scan rates that span the range of Brownian velocities of such emulsion drops. The adsorbed anionic surfactants impart a stabilising electrical double layer repulsion between the drops so coalescence was not observed under present conditions.