Electronic Structure最新文献_第10页

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn2 弱流动铁磁体ZrZn2发酵过程中的局域电子关联效应

IF 2.6

Electronic Structure Pub Date : 2022-08-23 DOI: 10.1088/2516-1075/ac9d79

Wenhan Chen, A. James, S. Dugdale

{"title":"Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn2","authors":"Wenhan Chen, A. James, S. Dugdale","doi":"10.1088/2516-1075/ac9d79","DOIUrl":"https://doi.org/10.1088/2516-1075/ac9d79","url":null,"abstract":"The Fermi surface topology plays an important role in the macroscopic properties of metals. It can be particularly sensitive to electron correlation, which appears to be especially significant for the weak itinerant ferromagnet ZrZn2. Here, we look at the differences in the predicted Fermi surface sheets of this metallic compound in its paramagnetic phase for both density functional theory (DFT) and the combination of DFT with dynamical mean field theory (DFT + DMFT). The theoretical spectral functions evaluated at the Fermi level were used along with calculations of the electron–positron momentum density (also known as the two-photon momentum density) in k-space to provide insights into the origin of certain features of the Fermi surface topology. We compare this two photon momentum density to that extracted from the positron annihilation experimental data (2004 Phys. Rev. Lett. 92 107003). The DFT + DMFT densities are in better agreement with the experiment than the DFT, particularly with regard to the flat bands around the L and W high symmetry points. The experimental neck around L, which relates to a van Hove singularity, is present in DFT + DMFT but not in the DFT. We find that these flat bands, and as such the Fermi surface topology, are sensitive to the many body electron correlation description, and show that the positron annihilation technique is able to probe this. This description is significant for the observed behavior such as the Lifshiftz transition around the quantum critical point.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":"4 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41524165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Floquet formulation of the dynamical Berry-phase approach to nonlinear optics in extended systems 扩展系统中非线性光学的动态berry相位法的Floquet公式

IF 2.6

Electronic Structure Pub Date : 2022-08-22 DOI: 10.1088/2516-1075/acbc5e

Ignacio M. Alliati, M. Grüning

引用次数: 0

Interface energetics make devices 界面能量构成器件

IF 2.6

Electronic Structure Pub Date : 2022-08-09 DOI: 10.1088/2516-1075/ac884d

S. Duhm

引用次数: 7

Recent progress in clean-surface formation of topological Kondo insulators and topological surface states observed there 拓扑近藤绝缘体清洁表面形成的最新进展和在那里观察到的拓扑表面态

IF 2.6

Electronic Structure Pub Date : 2022-08-02 DOI: 10.1088/2516-1075/ac8631

Y. Ohtsubo, S. Kimura, F. Iga

引用次数: 1

Suppression of charge-density-wave order in TiSe2 studied with high-pressure magnetoresistance 高压磁阻对TiSe2中电荷密度波序的抑制研究

IF 2.6

Electronic Structure Pub Date : 2022-07-29 DOI: 10.1088/2516-1075/ac858c

Owen Moulding, T. Muramatsu, C. Sayers, E. da Como, S. Friedemann

引用次数: 3

A deep investigation of NiO and MnO through the first principle calculations and Monte Carlo simulations 通过第一性原理计算和蒙特卡罗模拟深入研究NiO和MnO

IF 2.6

Electronic Structure Pub Date : 2022-07-25 DOI: 10.1088/2516-1075/acbff8

M. Alaei, H. Karimi

{"title":"A deep investigation of NiO and MnO through the first principle calculations and Monte Carlo simulations","authors":"M. Alaei, H. Karimi","doi":"10.1088/2516-1075/acbff8","DOIUrl":"https://doi.org/10.1088/2516-1075/acbff8","url":null,"abstract":"In this study, we use Hubbard-corrected density functional theory (DFT+U) to derive spin model Hamiltonians consisting of Heisenberg exchange interactions up to the fourth nearest neighbors and bi-quadratic interactions. We map the DFT+U results of several magnetic configurations to the Heisenberg spin model Hamiltonian to estimate Heisenberg exchanges. We demonstrate that the number of magnetic configurations should be at least twice the number of exchange parameters to estimate exchange parameters correctly. To calculate biquadratic interaction, we propose specific non-collinear magnetic configurations that do not change the energy of the Heisenberg spin model. We use classical Monte Carlo (MC) simulations to evaluate DFT+U results. We obtain the temperature dependence of magnetic susceptibility and specific heat to determine the Curie–Weiss and Néel temperatures. The MC simulations reveal that although the biquadratic interaction can not change the Néel temperature, it modifies the order parameter. We indicate that for a fair comparison between classical MC simulations and experiments, we need to consider the quantum effect by applying (S+1)/S correction in classical MC simulations.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42139748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Two routes to hydrogen evolution for a Co-polypyridyl complex with two open sites 具有两个开放位点的共聚吡啶配合物的两种析氢途径

IF 2.6

Electronic Structure Pub Date : 2022-06-23 DOI: 10.1088/2516-1075/ac7bca

Liqin Xue Toro, S. Kiriakidi, A. Thapper, S. Ott, M. Lundberg

{"title":"Two routes to hydrogen evolution for a Co-polypyridyl complex with two open sites","authors":"Liqin Xue Toro, S. Kiriakidi, A. Thapper, S. Ott, M. Lundberg","doi":"10.1088/2516-1075/ac7bca","DOIUrl":"https://doi.org/10.1088/2516-1075/ac7bca","url":null,"abstract":"Cobalt polypyridyl complexes efficiently catalyze hydrogen evolution in aqueous media and exhibit high stability under reducing conditions. Their stability and activity can be tuned through electronic and steric considerations, but the rationalization of these effects requires detailed mechanistic understanding. As an example, tetradentate ligands with two non-permanently occupied coordination sites show higher activity with these sites in cis compared to trans configuration. Here reaction mechanisms of the Co-polypyridyl complex [CoII(bpma)Cl2] (bpma = bipyridinylmethyl-pyridinylmethyl-methyl-amine) have been studied using hybrid density-functional theory. This complex has two exchangeable cis sites, and provides a flexible ligand environment with both pyridyl and amine coordination. Two main pathways with low barriers are found. One pathway, which includes both open sites, is hydrogen evolution from a CoII-H intermediate with a water ligand as the proton donor. In the second pathway H–H bond formation occurs between the hydride and the protonated bpma ligand, with one open site acting as a spectator. The two pathways have similar barriers at higher pH, while the latter becomes more dominant at lower pH. The calculations consider a large number of interconnected variables; protonation sites, isomers, spin multiplicities, and the identities of the open binding sites, as well as their combinations, thus exploring many simultaneous dimensions within each pathway. The results highlight the effects of having two open cis-coordination sites and how their relative binding affinities change during the reaction pathway. They also illustrate why CoII-H intermediates are more active than CoIII-H ones, and why pyridyl protonation gives lower reaction barriers than amine protonation.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44177003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

First-principles calculation of the parameters used by atomistic magnetic simulations 原子磁性模拟所用参数的第一性原理计算

IF 2.6

Electronic Structure Pub Date : 2022-06-20 DOI: 10.1088/2516-1075/ac89c3

S. Mankovsky, H. Ebert

{"title":"First-principles calculation of the parameters used by atomistic magnetic simulations","authors":"S. Mankovsky, H. Ebert","doi":"10.1088/2516-1075/ac89c3","DOIUrl":"https://doi.org/10.1088/2516-1075/ac89c3","url":null,"abstract":"While the ground state of magnetic materials is in general well described on the basis of spin density functional theory (SDFT), the theoretical description of finite-temperature and non-equilibrium properties require an extension beyond the standard SDFT. Time-dependent SDFT (TD-SDFT), which give for example access to dynamical properties are computationally very demanding and can currently be hardly applied to complex solids. Here we focus on the alternative approach based on the combination of a parameterized phenomenological spin Hamiltonian and SDFT-based electronic structure calculations, giving access to the dynamical and finite-temperature properties for example via spin-dynamics simulations using the Landau–Lifshitz–Gilbert (LLG) equation or Monte Carlo simulations. We present an overview on the various methods to calculate the parameters of the various phenomenological Hamiltonians with an emphasis on the KKR Green function method as one of the most flexible band structure methods giving access to practically all relevant parameters. Concerning these, it is crucial to account for the spin–orbit coupling (SOC) by performing relativistic SDFT-based calculations as it plays a key role for magnetic anisotropy and chiral exchange interactions represented by the DMI parameters in the spin Hamiltonian. This concerns also the Gilbert damping parameters characterizing magnetization dissipation in the LLG equation, chiral multispin interaction parameters of the extended Heisenberg Hamiltonian, as well as spin–lattice interaction parameters describing the interplay of spin and lattice dynamics processes, for which an efficient computational scheme has been developed recently by the present authors.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47548529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Graph-learning guided mechanistic insights into imipenem hydrolysis in GES carbapenemases

IF 2.6

Electronic Structure Pub Date : 2022-06-16 DOI: 10.1088/2516-1075/ac7993

Zilin Song, Peng-Chu Tao

{"title":"Graph-learning guided mechanistic insights into imipenem hydrolysis in GES carbapenemases","authors":"Zilin Song, Peng-Chu Tao","doi":"10.1088/2516-1075/ac7993","DOIUrl":"https://doi.org/10.1088/2516-1075/ac7993","url":null,"abstract":"Pathogen resistance to carbapenem antibiotics compromises effective treatments of superbug infections. One major source of carbapenem resistance is the bacterial production of carbapenemases which effectively hydrolyze carbapenem drugs. In this computational study, the deacylation reaction of imipenem (IPM) by GES-5 carbapenemases (GES) is modeled to unravel the mechanistic factors that facilitate carbapenem resistance. Hybrid quantum mechanical/molecular mechanical (QM/MM) calculations are applied to sample the GES/IPM deacylation barriers on the minimum energy pathways (MEPs). In light of the recent emergence of graph-based deep-learning techniques, we construct graph representations of the GES/IPM active site. An edge-conditioned graph convolutional neural network (ECGCNN) is trained on the acyl-enzyme conformational graphs to learn the underlying correlations between the GES/IPM conformations and the deacylation barriers. A perturbative approach is proposed to interpret the latent representations from the graph-learning (GL) model and extract essential mechanistic understanding with atomistic detail. In general, our study combining QM/MM MEPs calculations and GL models explains mechanistic landscapes underlying the IPM resistance driven by GES carbapenemases. We also demonstrate that GL methods could effectively assist the post-analysis of QM/MM calculations whose data span high dimensionality and large sample-size.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47754594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Green’s function methods for excited states and x-ray spectra of functional materials 功能材料激发态和x射线光谱的格林函数方法

IF 2.6

Electronic Structure Pub Date : 2022-06-14 DOI: 10.1088/2516-1075/ac78b4

J. Kas, F. Vila, T. Tan, J. Rehr

{"title":"Green’s function methods for excited states and x-ray spectra of functional materials","authors":"J. Kas, F. Vila, T. Tan, J. Rehr","doi":"10.1088/2516-1075/ac78b4","DOIUrl":"https://doi.org/10.1088/2516-1075/ac78b4","url":null,"abstract":"Many interesting properties of functional materials, such as dynamic response and thermodynamic behavior, depend on their excited state properties. These functional properties are often related to excitations in the system, such as phonons and plasmons, which lead to inelastic losses, lifetime, and other dynamic effects. The excitations are pure many-body correlation effects that are missing from independent particle theories. They are revealed in x-ray spectra such as photoemission and absorption, where they show up as satellites beyond the quasi-particle approximation. Our main focus in this work is the use of Green’s function methods to describe these effects. In particular, we discuss how the cumulant Green’s function provides a unified treatment of such dynamic correlation effects in many contexts. Besides a robust theoretical framework, these methods also yield widely applicable tools for practical calculations of many functional properties of materials. This methodology is illustrated with a number of applications ranging from optical and x-ray spectra to thermodynamic properties, and dynamic response. Some recent extensions for more correlated systems are also briefly discussed.","PeriodicalId":42419,"journal":{"name":"Electronic Structure","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2022-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42244675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0