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General invariance and equilibrium conditions for lattice dynamics in 1D,2D,and 3D materials

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npj Computational Materials 2022年第1期8卷 2280-2290页

作者： Changpeng Lin Samuel Poncé nicola.marzari Theory and Simulation of Materials(THEOS) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland European Theoretical Spectroscopy Facility Institute of Condensed Matter and NanosciencesUniversitécatholique de LouvainChemin desÉtoiles 8B-1348Louvain-la-NeuveBelgium

The long-wavelength behavior of vibrational modes plays a central role in carrier transport,phonon-assisted optical properties,superconductivity,and thermomechanical and thermoelectric properties of ***,we present general invariance and equilibrium conditions of the lattice potential;these allow to recover the quadratic dispersions of flexural phonons in low-dimensional materials,in agreement with the phenomenological model for long-wavelength bending *** also prove that for any low-dimensional material the bending modes can have a purely out-of-plane polarization in the vacuum direction and a quadratic dispersion in the long-wavelength *** addition,we propose an effective approach to treat invariance conditions in crystals with non-vanishing Born effective charges where the long-range dipole-dipole interactions induce a contribution to the lattice potential and stress *** approach is successfully applied to the phonon dispersions of 158 two-dimensional materials,highlighting its critical relevance in the study of phonon-mediated properties of low-dimensional materials.

关键词： materials. lattice invariance

Solids that are also liquids: elastic tensors of superionic materials

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npj Computational Materials 2023年第1期9卷 2252-2264页

作者： Giuliana Materzanini Tommaso Chiarotti nicola.marzari Theory and Simulations of Materials(THEOS) École Polytechnique Fédérale de LausanneCH-1015 LausanneSwitzerland National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneCH-1015 LausanneSwitzerland Present address:Institute of Condensed Matter and Nanosciences UniversitéCatholique de LouvainB-1348 Louvain-la-NeuveBelgium

Superionics are fascinating materials displaying both solid- and liquid-like characteristics: as solids, they respond elastically to shearstress;as liquids, they display fast-ion diffusion at normal conditions. In addition to such scientific interest, superionics aretechnologically relevant for energy, electronics, and sensing applications. Characterizing and understanding their elastic propertiesis, e.g., urgently needed to address their feasibility as solid-state electrolytes in all-solid-state batteries. However, static approachesto elasticity assume well-defined reference positions around which atoms vibrate, in contrast with the quasi-liquid motion of themobile ions in fast ionic conductors. Here, we derive the elastic tensors of superionics from ensemble fluctuations in the isobaric-isothermal ensemble, exploiting extensive Car-Parrinello simulations. We apply this approach to paradigmatic Li-ion conductors,and complement with a block analysis to compute statistical errors. Static approaches sampled over the trajectories oftenoverestimate the response, highlighting the importance of a dynamical treatment in determining elastic tensors in superionics.

关键词： ionic liquids ensemble

Thermal conductivity of glasses: first-principles theory and applications

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npj Computational Materials 2023年第1期9卷 1253-1274页

作者： Michele Simoncelli Francesco Mauri nicola.marzari Theory of Condensed Matter Group of the Cavendish Laboratory University of CambridgeCambridgeUK Dipartimento di Fisica Universitàdi Roma La SapienzaRomaItaly Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneLausanneSwitzerland

Predicting the thermal conductivity of glasses from first principles has hitherto been a very complex *** established Allen-Feldman and Green-Kubo approaches employ approximations with limited validity—the former neglects anharmonicity,the latter misses the quantum Bose-Einstein statistics of vibrations—and require atomistic models that are very challenging for first-principles ***,we present a protocol to determine from first principles the thermal conductivityκ(T)of glasses above the plateau(i.e.,above the temperature-independent region appearing almost without exceptions in theκ(T)of all glasses at cryogenic temperatures).The protocol combines the Wigner formulation of thermal transport with convergence-acceleration techniques,and accounts comprehensively for the effects of structural disorder,anharmonicity,and Bose-Einstein *** validate this approach in vitreous silica,showing that models containing less than 200 atoms can already reproduceκ(T)in the macroscopic *** discuss the effects of anharmonicity and the mechanisms determining the trend ofκ(T)at high temperature,reproducing experiments at temperatures where radiative effects remain negligible.

关键词： glasses conductivity harmonic

Automated mixing of maximally localized Wannier functions into target manifolds

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npj Computational Materials 2023年第1期9卷 229-237页

作者： Junfeng Qiao Giovanni Pizzi nicola.marzari Theory and Simulations of Materials(THEOS) and National Centre for Computational Design and Discovery of Novel Materials(MARVEL)École Polytechnique Fédérale de Lausanne1015 LausanneSwitzerland Laboratory for Materials Simulations(LMS) Paul Scherrer Institut(PSI)CH-5232 Villigen PSISwitzerland

Maximally localized Wannier functions(MLWFs)are widely used in electronic-structure *** have recently developed automated approaches to generate MLWFs that represent natural tight-binding sets of atomic-like orbitals;these describe accurately both the occupied states and the complementary unoccupied *** many applications,it is required to use MLWFs that describe instead certain target groups of bands:the valence or the conduction bands,or correlated ***,we start from these tight-binding sets of MLWFs,and mix them using a combination of parallel transport and maximal localization to construct manifold-remixed Wannier functions(MRWFs):these are orthogonal sets of MLWFs that fully and only span desired target *** algorithm is simple and robust,and is showcased here in reference applications(silicon,MoS_(2),and SrVO_(3))and in a mid-throughput study of 77 insulators.

关键词： maximal bands occupied

Projectability disentanglement for accurate and automated electronic-structure Hamiltonians

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npj Computational Materials 2023年第1期9卷 215-228页

Maximally-localized Wannier functions(MLWFs)are broadly used to characterize the electronic structure of ***,one can construct MLWFs describing isolated bands(*** bands of insulators)or entangled bands(*** and conduction bands of insulators,or metals).Obtaining accurate and compact MLWFs often requires chemical intuition and trial and error,a challenging step even for experienced researchers and a roadblock for high-throughput ***,we present an automated approach,projectability-disentangled Wannier functions(PDWFs),that constructs MLWFs spanning the occupied bands and their complement for the empty states,providing a tight-binding picture of optimized atomic orbitals in *** to the algorithm is a projectability measure for each Bloch state onto atomic orbitals,determining if that state should be kept identically,discarded,or mixed into the *** showcase the accuracy on a test set of 200 materials,and the reliability by constructing 21,737 Wannier Hamiltonians.

关键词： bands Hamiltonian electronic

Photorealistic modelling of metals from first principles

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npj Computational Materials 2019年第1期5卷 1-12页

作者： Gianluca Prandini Gian-Marco Rignanese nicola.marzari Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de Lausanne1015 LausanneSwitzerland Institute of Condensed Matter and Nanosciences(IMCN) Universitécatholique de Louivain1348 Louvain-la-NeuveBelgium

The colours of metals have attracted the attention of humanity since ancient times,and coloured metals,in particular gold compounds,have been employed for tools and objects symbolizing the aesthetics of *** this work,we develop a comprehensive framework to obtain the reflectivity and colour of metals,and show that the trends in optical properties and the colours can be predicted by straightforward first-principles techniques based on standard *** apply this to predict reflectivity and colour of several elemental metals and of different types of metallic compounds(intermetallics,solid solutions and heterogeneous alloys),considering mainly binary alloys based on noble *** validate the numerical approach through an extensive comparison with experimental data and the photorealistic rendering of known coloured metals.

关键词： alloys intermetallics metals

Electrosorption at metal surfaces from first principles

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npj Computational Materials 2020年第1期6卷 517-526页

作者： nicolas G.Hörmann nicola.marzari Karsten Reuter Chair of Theoretical Chemistry and Catalysis Research Center Technische Universität MünchenGarching 85748Germany Theory and Simulation of Materials(THEOS) and National Centre for Computational Design and Discovery of Novel Materials(MARVEL)École Polytechnique Fédérale de LausanneLausanne 1015Switzerland Fritz-Haber-Institut der Max-Planck-Gesellschaft Faradayweg 4-6Berlin 14195Germany

Electrosorption of solvated species at metal electrodes is a most fundamental class of processes in interfacial ***,we use its sensitive dependence on the electric double layer to assess the performance of ab initio thermodynamics approaches increasingly used for the first-principles description of *** show analytically that computational hydrogen electrode calculations at zero net-charge can be understood as a first-order approximation to a fully grand canonical ***,higher-order terms in the applied potential caused by the charging of the double layer include contributions from adsorbate-induced changes in the work function and in the interfacial *** contributions are essential to yield prominent electrochemical phenomena such as non-Nernstian shifts of electrosorption peaks and non-integer electrosorption *** illustrate this by calculating peak shifts for H on Pt electrodes and electrosorption valencies of halide ions on Ag electrodes,obtaining qualitative agreement with experimental data already when considering only second order *** results demonstrate the agreement between classical electrochemistry concepts and a first-principles fully grand canonical description of electrified interfaces and shed new light on the widespread computational hydrogen electrode approach.

关键词： sorption principles canonical

Thermodynamics and dielectric response of BaTiO_(3)by data-driven modeling

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npj Computational Materials 2022年第1期8卷 1998-2014页

作者： Lorenzo Gigli Max Veit Michele Kotiuga Giovanni Pizzi nicola.marzari Michele Ceriotti Laboratory of Computational Science and Modeling(COSMO) Institute of MaterialsÉcole Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland

Modeling ferroelectric materials from first principles is one of the successes of density-functional theory and the driver of much development effort,requiring an accurate description of the electronic processes and the thermodynamic equilibrium that drive the spontaneous symmetry breaking and the emergence of macroscopic *** demonstrate the development and application of an integrated machine learning model that describes on the same footing structural,energetic,and functional properties of barium titanate(BaTiO_(3)),a prototypical *** model uses ab initio calculations as a reference and achieves accurate yet inexpensive predictions of energy and polarization on time and length scales that are not accessible to direct ab initio *** predictions allow us to assess the microscopic mechanism of the ferroelectric *** presence of an order-disorder transition for the Ti off-centered states is the main driver of the ferroelectric transition,even though the coupling between symmetry breaking and cell distortions determines the presence of intermediate,partly-ordered ***,we thoroughly probe the static and dynamical behavior of BaTiO_(3)across its phase diagram without the need to introduce a coarse-grained description of the ferroelectric ***,we apply the polarization model to calculate the dielectric response properties of the material in a full ab initio manner,again reproducing the correct qualitative experimental behavior.

关键词： transition ferroelectric dielectric

Precision and efficiency in solid-state pseudopotential calculations

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npj Computational Materials 2018年第1期4卷 77-89页

作者： Gianluca Prandini Antimo Marrazzo Ivano E.Castelli nicolas Mounet nicola.marzari Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de Lausanne1015 LausanneSwitzerland Department of Energy Conversion and Storage Technical University of DenmarkDK-2800 Kgs.LyngbyDenmark

Despite the enormous success and popularity of density-functional theory,systematic verification and validation studies are still limited in number and ***,we propose a protocol to test publicly available pseudopotential libraries,based on several independent criteria including verification against all-electron equations of state and plane-wave convergence tests for phonon frequencies,band structure,cohesive energy and *** these criteria we obtain curated pseudopotential libraries(named SSSP or standard solid-state pseudopotential libraries),that we target for high-throughput materials screening(“SSSP efficiency”)and high-precision materials modelling(“SSSP precision”).This latter scores highest among open-source pseudopotential libraries available in theΔ-factor test of equations of states of elemental solids.

关键词： state solids latter