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Vibrationally resolved optical excitations of the nitrogen-vacancy center in diamond

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npj Computational Materials 2022年第1期8卷 2258-2266页

作者： Yu Jin Marco Govoni giulia galli Department of Chemistry University of ChicagoChicagoIL60637USA Pritzker School of Molecular Engineering University of ChicagoChicagoIL60637USA Materials Science Division and Center for Molecular Engineering Argonne National LaboratoryLemontIL60439USA

A comprehensive description of the optical cycle of spin defects in solids requires the understanding of the electronic and atomistic structure of states with different spin multiplicity,including singlet states which are particularly challenging from a theoretical *** present a general framework,based on spin-flip time-dependent density function theory,to determine the excited state potential energy surfaces of the many-body singlet states of spin defects;we then predict the vibrationally resolved absorption spectrum between singlet shelving states of a prototypical defect,the nitrogen-vacancy center in *** results,which are in very good agreement with experiments,provide an interpretation of the measured spectra and reveal the key role of specific phonons in determining absorption processes,and the notable influence of non-adiabatic *** insights gained from our calculations may be useful in defining strategies to improve infrared-absorption-based magnetometry and optical pumping *** theoretical framework developed here is general and applicable to a variety of other spin defects and materials.

关键词： vacancy resolved singlet

Understanding the metal-to-insulator transition in La_(1−x)Sr_(x)CoO_(3−δ) and its applications for neuromorphic computing

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npj Computational Materials 2020年第1期6卷 261-269页

作者： Shenli Zhang giulia galli Pritzker School of Molecular Engineering The University of ChicagoChicagoILUSA Argonne National Laboratory ArgonneILUSA Department of Chemistry The University of ChicagoChicagoILUSA

Transition metal oxides that exhibit a metal-to-insulator transition(MIT)as a function of oxygen vacancy concentration are promising systems to realize energy-efficient platforms for neuromorphic ***,the current lack of understanding of the microscopic mechanism driving the MIT hinders the realization of effective and stable *** we investigate defective cobaltites and we unravel the structural,electronic,and magnetic changes responsible for the MIT when oxygen vacancies are introduced in the *** show that,contrary to accepted views,cooperative structural distortions instead of local bonding changes are responsible for the MIT,and we describe the subtle interdependence of structural and magnetic ***,we present a model,based on first principles,to predict the required electric bias to drive the transition,showing good agreement with available measurements and providing a paradigm to establish design rules for low-energy cost devices.

关键词： transition insulator hinder

Spin coherence in two-dimensional materials

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npj Computational Materials 2019年第1期5卷 760-765页

作者： Meng Ye Hosung Seo giulia galli Institute for Molecular Engineering The University of ChicagoChicagoILUSA Materials Science Division Argonne National LaboratoryLemontILUSA Department of Physics Ajou UniversitySuwonRepublic of Korea Department of Energy Systems Research Ajou UniversitySuwonRepublic of Korea Department of Chemistry University of ChicagoChicagoILUSA Institute for Molecular Engineering Argonne National LaboratoryLemontILUSA

Spin defects in semiconducting solids are promising platforms for the realization of quantum *** low temperature and in the presence of a large magnetic field,the central spin decoherence is mainly due to the fluctuating magnetic field induced by nuclear spin flip-flop *** spin Hamiltonians and a cluster expansion method,we investigate the electron spin coherence of defects in two-dimensional(2D)materials,including delta-doped diamond layers,thin Si films,MoS_(2),and *** show that isotopic purification is much more effective in 2D than in three-dimensional materials,leading to an exceptionally long spin coherence time of more than 30 ms in an isotopically pure monolayer of MoS_(2).

关键词： exceptional realization solids

Quantum simulations of materials on near-term quantum computers

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npj Computational Materials 2020年第1期6卷 947-954页

作者： He Ma Marco Govoni giulia galli Department of Chemistry University of ChicagoChicagoIL 60637USA Materials Science Division and Center for Molecular Engineering Argonne National LaboratoryLemontIL 60439USA Pritzker School of Molecular Engineering University of ChicagoChicagoIL 60637USA

Quantum computers hold promise to enable efficient simulations of the properties of molecules and materials;however,at present they only permit ab initio calculations of a few atoms,due to a limited number of *** order to harness the power of near-term quantum computers for simulations of larger systems,it is desirable to develop hybrid quantum-classical methods where the quantum computation is restricted to a small portion of the *** is of particular relevance for molecules and solids where an active region requires a higher level of theoretical accuracy than its ***,we present a quantum embedding theory for the calculation of strongly-correlated electronic states of active regions,with the rest of the system described within density functional *** demonstrate the accuracy and effectiveness of the approach by investigating several defect quantum bits in semiconductors that are of great interest for quantum information *** perform calculations on quantum computers and show that they yield results in agreement with those obtained with exact diagonalization on classical architectures,paving the way to simulations of realistic materials on near-term quantum computers.

关键词： theory quantum exact

Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations

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npj Computational Materials 2021年第1期7卷 1108-1115页

作者： Krishnendu Ghosh He Ma Mykyta Onizhuk Vikram Gavini giulia galli Department of Mechanical Engineering University of MichiganAnn ArborMIUSA Pritzker School of Molecular Engineering University of ChicagoChicagoILUSA Department of Chemistry University of ChicagoChicagoILUSA Department of Materials Science and Engineering University of MichiganAnn ArborMIUSA Materials Science Division Argonne National LaboratoryLemontILUSA

Understanding the quantum dynamics of spin defects and their coherence properties requires an accurate modeling of spinspin interaction in solids and molecules,for example by using spin Hamiltonians with parameters obtained from first principles *** present a real-space approach based on density functional theory for the calculation of spin-Hamiltonian parameters,where only selected atoms are treated at the all-electron level,while the rest of the system is described with the pseudopotential *** approach permits calculations for systems containing more than 1000 atoms,as demonstrated for defects in diamond and silicon *** show that only a small number of atoms surrounding the defect needs to be treated at the all-electron level,in order to obtain an overall all-electron accuracy for hyperfine and zero-field splitting *** also present results for coherence times,computed with the cluster correlation expansion method,highlighting the importance of accurate spin-Hamiltonian parameters for quantitative predictions of spin dynamics.

关键词： dynamics solids Hamiltonian

Code interoperability extends the scope of quantum simulations

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npj Computational Materials 2021年第1期7卷 302-311页

作者： Marco Govoni Jonathan Whitmer Juan de Pablo Francois Gygi giulia galli Materials Science Division and Center for Molecular Engineering Argonne National LaboratoryLemontIL 60439USA Department of Chemical and Biomolecular Engineering University of Notre DameNotre DameIN 46556USA Pritzker School of Molecular Engineering University of ChicagoChicagoIL 60637USA Department of Computer Science University of CaliforniaDavisCA 95616USA Department of Chemistry University of ChicagoChicagoIL 60637USA

The functionality of many materials is critically dependent on the integration of dissimilar components and on the interfaces that arise between *** 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’*** 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 *** 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.

关键词： quantum catalysis spectroscopic

Author Correction:Spin–spin interactions in defects in solids from mixed all-electron and pseudopotential first-principles calculations

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npj Computational Materials 2021年第1期7卷 1143-1143页

作者： Krishnendu Ghosh He Ma Mykyta Onizhuk Vikram Gavini giulia galli University of Michigan Department of Mechanical Engineering Ann Arbor USA (GRID:grid.214458.e) (ISNI:***) Intel Corporation Computational and Modeling Technology Hillsboro USA (GRID:grid.419318.6) (ISNI:0000 0004 1217 7655) University of Chicago Pritzker School of Molecular Engineering Chicago USA (GRID:grid.170205.1) (ISNI:0000 0004 1936 7822) University of Chicago Department of Chemistry Chicago USA (GRID:grid.170205.1) (ISNI:0000 0004 1936 7822) University of Michigan Department of Mechanical Engineering Ann Arbor USA (GRID:grid.214458.e) (ISNI:***) University of Michigan Department of Materials Science and Engineering Ann Arbor USA (GRID:grid.214458.e) (ISNI:***) University of Chicago Pritzker School of Molecular Engineering Chicago USA (GRID:grid.170205.1) (ISNI:0000 0004 1936 7822) University of Chicago Department of Chemistry Chicago USA (GRID:grid.170205.1) (ISNI:0000 0004 1936 7822) Argonne National Laboratory Materials Science Division Lemont USA (GRID:grid.187073.a) (ISNI:0000 0001 1939 4845)

The original version of this Article contained an error in Fig.2,in which the colour coding of the legend,depicting the data for‘PWPAW’and‘FE-AE’,is *** has been corrected in both the PDF and HTML versions of the ... 详细信息

关键词： HTML solids principles

Thermo-optically induced transparency on a photonic chip

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Light(Science & Applications) 2021年第12期10卷 2482-2491页

作者： Marco Clementi Simone Iadanza Sebastian A.Schulz giulia Urbinati Dario Gerace Liam O’Faloain Matteo galli Dipartimento di Fisica Universitàdi PaviaVia A.Bassi 627100 PaviaItaly Centre for Advanced Photonics and Process Analysis Munster Technological UniversityRossa Ave BishopstownCorkT12 P928Ireland Tyndall National Institute Lee Maltings Complex Dyke ParadeCorkT12 R5CPIreland SUPA School of Physics and AstronomyUniversity of St.AndrewsFifeKY169SSUK Present address:École Polytechnique Fédérale de Lausanne Photonic Systems Laboratory(PHOSL)STI-IELStation 11Lausanne1015Switzerland

Controlling the optical response of a medium through suitably tuned coherent electromagnetic fields is highly relevant in a number of potential applications,from all-optical modulators to optical storage *** particular,electromagnetically induced transparency(EIT)is an established phenomenon in which destructive quantum interference creates a transparency window over a narrow spectral range around an absorption line,which,in turn,allows to slow and ultimately stop light due to the anomalous refractive index *** we report on the observation of a new form of both induced transparency and amplification of a weak probe beam in a strongly driven silicon photonic crystal resonator at room *** effect is based on the oscillating temperature field induced in a nonlinear optical cavity,and it reproduces many of the key features of EIT while being independent of either atomic or mechanical *** thermo-optically induced transparency will allow a versatile implementation of EIT-analogs in an integrated photonic platform,at almost arbitrary wavelength of interest,room temperature and in a practical,low cost,and scalable system.

关键词： temperature transparency oscillating