相关论文: Hidden structure in amorphous solids
The electronic structure of finite-length armchair carbon nanotubes has been studied using several ab-initio and semi-empirical quantum computational techniques. The additional confinement of the electrons along the tube axis leads to the…
Lattices with a basis can host crystallographic defects which share the same topological charge (e.g.~the Burgers vector $\vec b$ of a dislocation) but differ in their microscopic structure of the core. We demonstrate that in insulators…
The dimensionality of a correlated many-body system has a large impact on its electronic properties. When electrons are confined to one-dimensional chains of atoms their behavior is very different than in higher dimensional systems because…
Band structure determines the motion of electrons in a solid, giving rise to exotic phenomena when properly engineered. Drawing an analogy between electrons and photons, artificially designed optical lattices indicate the possibility of a…
The generalized tight-binding model has been developed to thoroughly explore the essential electronic and optical properties of AB-bt bilayer silicene. They are greatly diversified by the buckled structure, stacking configuration,…
Two-mode valence electron configuration of carbon atoms lays the foundation of the unique two-mode amorphous state of the monoatomic carbon solid. From the fundamentals of solid-state physics, sp$^3$ and sp$^2$ amorphous carbons are two…
A theory of the long wavelength low energy electronic structure of graphite-derived nanotubules is presented. The propagating $\pi$ electrons are described by wrapping a massless two dimensional Dirac Hamiltonian onto a curved surface. The…
The buffer carbon layer obtained in the first instance by evaporation of Si from the Si-rich surfaces of silicon carbide (SiC) is often studied only as the intermediate to the synthesis of SiC supported graphene. In this work, we explore…
We investigated the microscopic and electronic structures amorphous oxide semiconductors InGaZnO$_{4}$ (a-IGZO) and the role of O-deficiency through the first-principle calculations. The structure of the amorphous oxide is complicated by…
A structural model of hydrogenated amorphous silicon containing an isolated dangling bond is used to investigate the effects of electron interactions on the electronic level splittings, localization of charge and spin, and fluctuations in…
We have used tight-binding molecular-dynamics simulations to investigate the role of point defects (vacancies and interstitials) on structural relaxation in amorphous silicon. Our calculations give unambiguous evidence that point defects…
Modeling the electronic and optical properties of organic semiconductors remains a challenge for theory, despite the remarkable progress achieved in the last three decades. The complexity of these systems, including structural (dis)order…
Spin-active color centers are the basis of solid-state defect systems utilized in quantum technologies. Although silicon is an emerging host material for quantum defects, there is an urgent need to characterize color centers with a non-zero…
We employ scanning probe microscopy to reveal atomic structures and nanoscale morphology of graphene-based electronic devices (i.e. a graphene sheet supported by an insulating silicon dioxide substrate) for the first time. Atomic resolution…
We demonstrate the existence of atomically-sized topological solitons in a quasi one-dimensional charge density wave system: indium atomic wires on Si(111). Performing joint scanning tunneling microscopy and density-functional calculations,…
Electronic and structural properties of a 3D carbon allotrope made of Hopf-linked graphenes, which we call a Hopfene - a type of topological crystal, are examined by semi-empirical molecular-orbital and density-functional-theoretical…
We present a computational study of small-angle X-ray scattering (SAXS) in amorphous silicon ($a$-Si) with particular emphasis on the morphology and microstructure of voids. The relationship between the scattering intensity in SAXS and the…
Recent experiments on hydrogenated amorphous silicon using infrared absorption spectroscopy have indicated the presence of mono- and divacancy in samples for concentration of up to 14\% hydrogen. Motivated by this observation, we study the…
We have carried out scanning tunneling spectroscopy measurements on exfoliated monolayer graphene on SiO$_2$ to probe the correlation between its electronic and structural properties. Maps of the local density of states are characterized by…
The geometric properties of a lattice can have profound consequences on its band spectrum. For example, symmetry constraints and geometric frustration can give rise to topologicially nontrivial and dispersionless bands, respectively.…