A5021610091- Advanced Chemical Physics Studies
- Electronic and Structural Properties of Oxides
- Diamond and Carbon-based Materials Research
- Spectroscopy and Quantum Chemical Studies
- Semiconductor materials and devices
- Machine Learning in Materials Science
- Silicon Nanostructures and Photoluminescence
- Quantum and electron transport phenomena
- High-pressure geophysics and materials
- Quantum Dots Synthesis And Properties
- Physics of Superconductivity and Magnetism
- Quantum, superfluid, helium dynamics
- Quantum Computing Algorithms and Architecture
- Chemical and Physical Properties of Materials
- Semiconductor Quantum Structures and Devices
- Advancements in Semiconductor Devices and Circuit Design
- IoT and Edge/Fog Computing
- Acoustic Wave Resonator Technologies
- Nanowire Synthesis and Applications
- Scientific Computing and Data Management
- Context-Aware Activity Recognition Systems
- Silicon and Solar Cell Technologies
- Atmospheric Ozone and Climate
- Perovskite Materials and Applications
- Advanced Semiconductor Detectors and Materials
Argonne National Laboratory
2015-2024
University of Chicago
2015-2024
University of Modena and Reggio Emilia
2010-2024
University of Ferrara
2016-2023
Alex's Lemonade Stand Foundation
2021
Acciai Speciali Terni (Italy)
2015
Tecnic (Italy)
2015
Trenitalia (Italy)
2015
Istituto Nanoscienze
2011
A self-consistent scheme for determining the optimal fraction of exact exchange full-range hybrid functionals is presented and applied to calculation band gaps dielectric constants solids. The exchange-correlation functional defined in a similar manner PBE0 functional, but mixing parameter set equal inverse macroscopic function it determined self-consistently by computing screening. We found excellent agreement with experiments properties broad class systems, ranging between 0.7 21.7 eV...
We present GW calculations of molecules, ordered and disordered solids interfaces, which employ an efficient contour deformation technique for frequency integration do not require the explicit evaluation virtual electronic states nor inversion dielectric matrices. also a parallel implementation algorithm, takes advantage separable expressions both single particle Green's function screened Coulomb interaction. The method can be used starting from density functional theory performed with...
We present an implementation of G0W0 calculations including spin-orbit coupling (SOC) enabling investigations large systems, with thousands electrons, and we discuss results for molecules, solids, nanocrystals. Using a newly developed set molecules heavy elements (called GW-SOC81), find that, when based upon hybrid density functional calculations, fully relativistic (FR) scalar-relativistic (SR) vertical ionization potentials both yield excellent performance compared to experiment, errors...
Abstract Quantum computers hold promise to enable efficient simulations of the properties molecules and materials; however, at present they only permit ab initio calculations a few atoms, due limited number qubits. In order harness power near-term quantum for larger systems, it is desirable develop hybrid quantum-classical methods where computation restricted small portion system. This particular relevance solids an active region requires higher level theoretical accuracy than its...
Electronic structure calculations have been instrumental in providing many important insights into a range of physical and chemical properties various molecular solid-state systems. Their importance to fields, including materials science, sciences, computational chemistry device physics, is underscored by the large fraction available public supercomputing resources devoted these calculations. As we enter exascale era, exciting new opportunities increase simulation numbers, sizes, accuracies...
Dielectric-dependent hybrid (DDH) functionals were recently shown to yield accurate energy gaps and dielectric constants for a wide variety of solids, at computational cost considerably less than that $\mathit{GW}$ calculations. The fraction exact exchange included in the definition DDH depends (self-consistently) on constant material. Here we introduce range-separated (RS) version where short- long-range components are matched using system-dependent, nonempirical parameters. We show RS-DDHs...
Abstract Understanding redox and photochemical reactions in aqueous environments requires a precise knowledge of the ionization potential electron affinity liquid water. The former has been measured, but not latter. We predict water its surface from first principles, coupling path-integral molecular dynamics with ab initio potentials, many-body perturbation theory. Our results for (0.8 eV) agree well recent pump-probe spectroscopy measurements on amorphous ice. Those bulk (0.1–0.3 differ...
The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of specification, v1.0, which is already supported by many leading several software packages. illustrate advantages OPTIMADE API through worked examples on each public that support full specification.
Quantum embedding theories are promising approaches to investigate strongly-correlated electronic states of active regions large-scale molecular or condensed systems. Notable examples spin defects in semiconductors and insulators. We present a detailed derivation quantum theory recently introduced, which is based on the definition effective Hamiltonians. The effect environment chosen space accounted for through screened Coulomb interactions evaluated using density functional theory....
We present a Green's function formulation of the quantum defect embedding theory (QDET) where double counting scheme is rigorously derived within G0W0 approximation. then show robustness our methodology by applying with newly to several defects in diamond. Additionally, we discuss strategy obtain converged results as size and composition active space. Our that QDET promising approach investigate strongly correlated states solids.
The reproducibility of calculations carried out within many-body perturbation theory at the G0W0 level is assessed for 100 closed shell molecules and compared to that density functional theory. We consider vertical ionization potentials (VIP) electron affinities (VEA) obtained with five different codes: BerkeleyGW, FHI-aims, TURBOMOLE, VASP, WEST. review approximations parameters control accuracy results in each code, we discuss detail effect extrapolation techniques entering WEST code....
We present a combined computational and experimental study of the photoelectron spectrum simple aqueous solution NaCl. Measurements were conducted on microjets, first-principles calculations performed using hybrid functionals many-body perturbation theory at G0W0 level, starting with wave functions computed in ab initio molecular dynamics simulations. show excellent agreement between experiments for positions both solute solvent excitation energies an absolute energy scale peak intensities....
Abstract Spin defects in wide-band gap semiconductors are promising systems for the realization of quantum bits, or qubits, solid-state environments. To date, defect qubits have only been realized materials with strong covalent bonds. Here, we introduce a strain-driven scheme to rationally design spins functional ionic crystals, which may operate as potential qubits. In particular, using combination state-of-the-art ab-initio calculations based on hybrid density and many-body perturbation...
The development of novel quantum bits is key to extend the scope solid-state information science and technology. Using first-principles calculations, we propose that large metal ion - vacancy complexes are promising qubit candidates in two binary crystals: 4H-SiC w-AlN. In particular, found formation neutral Hf- Zr-vacancy energetically favorable both solids; these defects have spin-triplet ground states, with electronic structures similar those diamond NV center SiC di-vacancy....
Interactions between light and matter are of fundamental interest in a variety fields, such as solar-energy conversion. A new, accurate method, based on first principles, is used to predict the absorption emission properties range organic inorganic molecules.
We derive a dielectric-dependent hybrid functional which accurately describes the electronic properties of heterogeneous interfaces and surfaces, as well those three- two-dimensional bulk solids. The functional, does not contain any adjustable parameter, is generalization self-consistent functionals introduced for homogeneous solids, where screened Coulomb interaction defined using spatially varying, local dielectric function. latter determined self-consistently density calculations in...
Many-body perturbation theory is a powerful method to simulate electronic excitations in molecules and materials starting from the output of density functional calculations. By implementing efficiently so as run at scale on latest leadership high-performance computing systems it possible extend scope GW We present GPU acceleration study full-frequency implemented WEST code. Excellent performance achieved through use (i) optimized libraries, e.g., cuFFT cuBLAS, (ii) hierarchical...
We present calculations of the ground and excited state energies spin defects in solids carried out on a quantum computer, using hybrid classical/quantum protocol. focus negatively charged nitrogen vacancy center diamond double 4H-SiC, which are interest for realization technologies. employ recently developed first-principle embedding theory to describe point embedded periodic crystal, derive an effective Hamiltonian, is then transformed qubit Hamiltonian by means parity transformation. use...
Abstract A comprehensive description of the optical cycle spin defects in solids requires understanding electronic and atomistic structure states with different multiplicity, including singlet which are particularly challenging from a theoretical standpoint. We present general framework, based on spin-flip time-dependent density function theory, to determine excited state potential energy surfaces many-body defects; we then predict vibrationally resolved absorption spectrum between shelving...
We present a formulation of spin-conserving and spin-flip hybrid time-dependent density functional theory (TDDFT), including the calculation analytical forces, which allows for efficient calculations excited state properties solid-state systems with hundreds to thousands atoms. discuss an implementation on both GPU- CPU-based architectures along several acceleration techniques. then apply our study point defects in semiconductors insulators, specifically negatively charged nitrogen-vacancy...
A predictive and efficient computational framework for describing the electronic properties of aqueous solutions is presented.