Charge state and entropic effects affecting the formation and dynamics of divacancies in 3C-SiC
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Zhang, Cunzhi↗
Engineering topics
Gygi, Francois
Publications and source records attributed to Gygi, Francois.
Engineering the formation of spin-defects from first principles
The full realization of spin qubits for quantum technologies relies on the ability to control and design the formation processes of spin defects in semiconductors and insulators. We present a computational protocol to investigate the synthesis of point-defects at the atomistic level, and we apply it to the study of a promising spin-qubit in silicon carbide, the divacancy (VV). Our strategy combines electronic structure calculations based on density functional theory and enhanced sampling techniques coupled with first principles molecular dynamics. We predict the optimal annealing temperatures for the formation of VVs at high temperature and show how to engineer the Fermi level of the material to optimize the defect’s yield for several polytypes of silicon carbide. Our results are in excellent agreement with available experimental data and provide novel atomistic insights into point defect formation and annihilation processes as a function of temperature.
36 MATERIALS SCIENCE↗
Quantum simulations of thermally activated delayed fluorescence in an all-organic emitter
The prototypical NAI-DMAC TADF emitter is investigated in the gas phase- and high-packing fraction limits at finite temperature, by combining first principles molecular dynamics with a quantum thermostat to account for nuclear quantum effects (NQE).
Francese, Tommaso↗
Quantum vibronic effects on the electronic properties of solid and molecular carbon
Here, we study the effect of quantum vibronic coupling on the electronic properties of carbon allotropes, including molecules and solids, by combining path integral first principles molecular dynamics (FPMD) with a colored noise thermostat. In addition to avoiding several approximations commonly adopted in calculations of electron-phonon coupling, our approach only adds a moderate computational cost to FPMD simulations and hence it is applicable to large supercells, such as those required to describe amorphous solids. We predict the effect of electron-phonon coupling on the fundamental gap of amorphous carbon, and we show that in diamond the zero-phonon renormalization of the band gap is larger than previously reported.
36 MATERIALS SCIENCE↗
Capturing the Complete Reaction Profile of a C?H Bond Activation
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Gygi, David↗
Code interoperability extends the scope of quantum simulations
The functionality of many materials is critically dependent on the integration of dissimilar components and on the interfaces that arise between them. The description of such heterogeneous components requires the development and deployment of first principles methods, coupled to appropriate dynamical descriptions of matter and advanced sampling techniques, in order to capture all the relevant length and time scales of importance to the materials’ performance. It is thus essential to build simple, streamlined computational schemes for the prediction and design of multiple properties of broad classes of materials, by developing interoperable codes which can be efficiently coupled to each other to perform complex tasks. We discuss the use of interoperable codes to simulate the structural and spectroscopic characterization of materials, including chemical reactions for catalysis, the description of defects for quantum information science, and heat and charge transport.
36 MATERIALS SCIENCE↗