A5033437756- Graphene research and applications
- Semiconductor materials and devices
- Advanced Chemical Physics Studies
- Diamond and Carbon-based Materials Research
- 2D Materials and Applications
- Molecular Junctions and Nanostructures
- ZnO doping and properties
- Spectroscopy and Quantum Chemical Studies
- High-pressure geophysics and materials
- Quantum and electron transport phenomena
- Silicon Carbide Semiconductor Technologies
- Boron and Carbon Nanomaterials Research
- Metal and Thin Film Mechanics
- Topological Materials and Phenomena
- Carbon Nanotubes in Composites
- Silicon Nanostructures and Photoluminescence
- Electronic and Structural Properties of Oxides
- Ga2O3 and related materials
- Semiconductor materials and interfaces
- GaN-based semiconductor devices and materials
- Quantum Dots Synthesis And Properties
- Machine Learning in Materials Science
- Advanced Photocatalysis Techniques
- MXene and MAX Phase Materials
- Copper-based nanomaterials and applications
University of Bremen
2016-2025
Beijing Computational Science Research Center
2020-2025
Chengdu University
2024-2025
Constructor University
2023-2025
Constructing Excellence
2024-2025
Tokyo University of Agriculture and Technology
2020
Can Tho University
2020
National Institutes for Quantum Science and Technology
2020
University of Rome Tor Vergata
2001-2015
Paderborn University
1999-2011
We outline details about an extension of the tight-binding (TB) approach to improve total energies, forces, and transferability. The method is based on a second-order expansion Kohn-Sham energy in density-functional theory (DFT) with respect charge density fluctuations. zeroth order equivalent common standard non-self-consistent scheme, while at second transparent, parameter-free, readily calculable expression for generalized Hamiltonian matrix elements may be derived. These are modified by...
We present a density-functional-based scheme for determining the necessary parameters of common nonorthogonal tight-binding (TB) models within framework linear-combination-of-atomic-orbitals formalism using local-density approximation (LDA). By only considering two-center integrals Hamiltonian and overlap matrix elements are calculated out suitable input densities potentials rather than fitted to experimental data. can derive analytical functions C-C, C-H, H-H elements. The usual short-range...
A new Fortran 95 implementation of the DFTB (density functional-based tight binding) method has been developed, where sparsity system equations exploited. Conventional dense algebra is used only to evaluate eigenproblems and long-range Coulombic terms, but drop-in O(N) or O(N2) modules are planned replace small code sections that these entail. The developed sparse storage structure discussed in detail, a short overview other features given.
We extend an approximate density functional theory (DFT) method for the description of long-range dispersive interactions which are normally neglected by construction, irrespective correlation function applied. An empirical formula, consisting R−6 term is introduced, appropriately damped short distances; corresponding C6 coefficient, calculated from experimental atomic polarizabilities, can be consistently added to total energy expression method. apply this DFT plus dispersion describe...
Recent reports on the fabrication of phosphorene, that is, mono- or few-layer black phosphorus, have raised exciting prospects an outstanding two-dimensional (2D) material exhibits excellent properties for nanodevice applications. Here, we study by first-principles calculations adsorption CO, CO2, NH3, NO, and NO2 gas molecules a monolayer phosphorene. Our results predict superior sensing performance phosphorene rivals even surpasses other 2D materials such as graphene MoS2. We determine...
DFTB+ is a versatile community developed open source software package offering fast and efficient methods for carrying out atomistic quantum mechanical simulations. By implementing various approximating density functional theory (DFT), such as the based tight binding (DFTB) extended method, it enables simulations of large systems long timescales with reasonable accuracy while being considerably faster typical than respective ab initio methods. Based on DFTB framework, additionally offers...
A simplified LCAO-DFT-LDA scheme for calculations of structure and electronic large molecules, clusters, solids is presented. Forces on the atoms are calculated in a semiempirical way considering states. The small computational effort this treatment allows one to perform molecular dynamics (MD) simulations molecules clusters up few hundred as well corresponding condensed systems within Born-Oppenheimer approximation. accuracy method illustrated by results series clusters. © 1996 John Wiley &...
A quantum mechanical/molecular mechanical (QM/MM) approach based on an approximate density functional theory, the so-called self-consistent charge tight binding (SCC-DFTB) method, has been implemented in CHARMM program and tested a number of systems biological interest. In gas phase, SCC-DFTB gives reliable energetics for models triosephosphate isomerase (TIM) catalyzed reactions. The rms errors compared to B3LYP/6-31+G(d,p) are about 2−4 kcal/mol; this is be contrasted with AM1, where...
We outline recent developments in quantum mechanical atomistic modelling of complex materials properties that combine the efficiency semi-empirical quantum-chemistry and tight-binding approaches with accuracy transferability more sophisticated density-functional post-Hartree-Fock methods aim to perform highly predictive simulations technological relevant sizes physics, chemistry biology. Following Harris, Foulkes Haydock, are based on an expansion Kohn-Sham total energy theory (DFT) respect...
The present status of development the density-functional-based tight-binding (DFTB) method is reviewed. As a two-centre approach to density-functional theory (DFT), it combines computational efficiency with reliability and transferability. Utilizing minimal-basis representation Kohn-Sham eigenstates superposition optimized neutral-atom potentials related charge densities for constructing effective many-atom potential, all integrals are calculated within DFT. Self-consistency included at...
We investigate the crossover regime from three dimensional topological insulators $Bi_2Te_3$ and $Bi_2Se_3$ to two with quantum spin Hall effect when layer thickness is reduced. Using both analytical models first-principles calculations, we find that occurs in an oscillatory fashion as a function of thickness, alternating between topologically trivial non-trivial behavior.
Structural and electronic properties as well the stability of MoS2 nanotubes are studied using density-functional-based tight-binding method. It is found that zigzag ( n,0) exhibit a narrow direct band gap armchair n,n) possess nonzero moderate gap. Interestingly, tubes show small indirect similar to nanotubes. Simulated electron diffraction patterns confirm existence disulphide The structure nanotube tips explained by introducing topological defects which produce positive negative curvature.
Two-dimensional (2D) materials with planar hypercoordinate motifs are extremely rare due to the difficulty in stabilizing configurations extended systems. Furthermore, such exotic often unstable. We predict a novel Cu2Si 2D monolayer featuring hexacoordinate copper and silicon. This is global minimum space which displays reduced dimensionality rule-breaking chemical bonding. system has been studied density functional theory, including molecular dynamics simulations electronic structure...
Defect levels are a problem for standard implementations of density-functional theory and the error also influences energetics. We demonstrate that HSE06 functional, which describes electronic structure all group-IV semiconductors well (including Ge), gives highly accurate charge transition levels, too, if defect wave function is host related---independent localization. The degree fulfilling generalized Koopmans' theorem shows reliability results highest-occupied eigenvalue always seems to...
Great enthusiasm in single-atom catalysts (SACs) for the nitrogen reduction reaction (NRR) has been aroused by discovery of metal–Nx as a promising catalytic center. However, poor activity and low selectivity available SACs are far away from industrial requirement. Through first-principles high-throughput screening, we find that Fe–Fe distributed on graphite carbon nitride (Fe2/g-CN) can manipulate binding strength target species (compromises ability to adsorb N2H NH2), therefore achieving...
Currently, there is no systematic way to describe a quantum process with memory solely in terms of experimentally accessible quantities. However, recent technological advances mean we have control over systems at scales where effects are non-negligible. The lack such an operational description has hindered understanding physical, chemical and biological processes, often unjustified theoretical assumptions made render dynamical tractable. This led theories plagued unphysical results consensus...
Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) provides an efficient way to obtain high-value-added biomass-derived chemicals. Compared with other transition metal oxides, CuO exhibits poor oxygen evolution reaction performance, leading high Faraday efficiency for HMF oxidation. However, the weak adsorption and activation ability OH- species restricts its further development. Herein, CuO-PdO heterogeneous interface is successfully constructed, resulting in advanced...
Effective modulation of physical properties via external control may open various potential nanoelectronic applications single-layer MoS2 nanoribbons (MoS2NRs). We show by first-principles calculations that the magnetic and electronic zigzag MoS2NRs exhibit sensitive response to applied strain electric field. Tensile in direction produces reversible moments phase transitions among metallic, half-metallic, semiconducting states, which stem from energy-level shifts induced an internal...
We derive a necessary and sufficient condition for quantum process to be Markovian which coincides with the classical one in relevant limit. Our unifies all previously known definitions Markov processes by accounting potentially detectable memory effects. then family of measures non-Markovianity clear operational interpretations, such as size required simulate process, or experimental falsifiability hypothesis.
Layered materials exhibit intriguing electronic characteristics and the search for new types of two-dimensional (2D) structures is importance future device fabrication. Using state-of-art first principle calculations, we identify characterize structural properties two 2D layered arsenic materials, namely, its alloy AsSb. The stable configuration confirmed to be low-buckled hexagonal structure by phonon binding energy calculations. monolayer exhibits indirect semiconducting with gap around...
Due to its wide band gap and availability as a single crystal, $\ensuremath{\beta}\ensuremath{-}\mathrm{G}{\mathrm{a}}_{2}{\mathrm{O}}_{3}$ has potential for applications in many areas of micro/optoelectronics photovoltaics. Still, little is yet known about intrinsic defects, which may influence carrier concentrations act recombination centers. From theoretical point view, the problem that standard (semi)local approximations density functional theory usually cannot handle band-gap oxides,...
Formation and excitation energies as well charge transition levels are determined for the substitutional nitrogen (N${}_{\mathrm{s}}$), vacancy (V), related point defects (NV, NVH, N${}_{2}$, N${}_{2}$V, V${}_{2}$) by screened nonlocal hybrid density functional supercell plane wave calculations in bulk diamond. In addition, activation energy V NV diffusion is calculated. We find good agreement between theory experiment previously well-established data predict missing ones. Based on...
Nanomaterials are prone to influence by chemical adsorption because of their large surface volume ratios. This enables sensitive detection adsorbed species which, in turn, can tune the property host material. Recent studies discovered that single and multilayer molybdenum disulfide (MoS_2) films ultra several important environmental molecules. Here we report new findings from ab initio calculations reveal substantially enhanced NO NH3 on strained monolyaer MoS2 with significant impact...
Abstract Molybdenum disulfide (MoS 2 ) is a promising alternative to Pt‐based catalysts for electrocatalytic hydrogen evolution reaction (HER) in an acidic environment. However, alkaline HER activity molybdenum limited by its slow water dissociation kinetics. Interface engineering effective strategy the design of catalysts. restricted heterointerfaces current have significantly their performance. Herein, novel assembly cobalt‐doped interface‐ and defect‐rich MoS /Ni 3 S hetero‐nanosheet...