Spin excitations play a fundamental role in understanding magnetic properties of materials,and have significant technological implications for magnonic devices.However,accurately modeling these in transition-metal and...Spin excitations play a fundamental role in understanding magnetic properties of materials,and have significant technological implications for magnonic devices.However,accurately modeling these in transition-metal and rare-earth compounds remains a formidable challenge.Here,we present a fully first-principles approach for calculating spin-wave spectra based on time-dependent(TD)density-functional perturbation theory(DFPT),using nonempirical Hubbard functionals.This approach is implemented in a general noncollinear formulation,enabling the study of magnons in both collinear and noncollinear magnetic systems.Unlike methods that rely on empirical Hubbard U parameters to describe the ground state,and Heisenberg Hamiltonians for describing magnetic excitations,the methodology developed here probes directly the dynamical spin susceptibility(efficiently evaluated with TDDFPT throught the Liouville-Lanczos approach),and treats the linear variation of the Hubbard augmentation(in itself calculated non-empirically)in full at a self-consistent level.Furthermore,the method satisfies the Goldstone condition without requiring empirical rescaling of the exchange-correlation kernel or explicit enforcement of sum rules,in contrast to existing state-of-the-art techniques.We benchmark the novel computational scheme on prototypical transition-metal monoxides NiO and MnO,showing remarkable agreement with experiments and highlighting the fundamental role of these newly implemented Hubbard corrections.The method holds great promise for describing collective spin excitations in complex materials containing localized electronic states.展开更多
Maximally-localized Wannier functions(MLWFs)are widely employed as an essential tool for calculating the physical properties of materials due to their localized nature and computational efficiency.Projectability-disen...Maximally-localized Wannier functions(MLWFs)are widely employed as an essential tool for calculating the physical properties of materials due to their localized nature and computational efficiency.Projectability-disentangled Wannier functions(PDWFs)have recently emerged as a reliable and efficient approach for automatically constructing MLWFs that span both occupied and lowest unoccupied bands.Here,we extend the applicability of PDWFs to magnetic systems and/or those including spin-orbit coupling,and implement such extensions in automated workflows.Furthermore,we enhance the robustness and reliability of constructing PDWFs by defining an extended protocol that automatically expands the projectors manifold,when required,by introducing additional appropriate hydrogenic atomic orbitals.We benchmark our extended protocol on a set of 200 chemically diverse materials,as well as on the 40 systems with the largest band distance obtained with the standard PDWF approach,showing that on our test set the present approach delivers a success rate of over 98%in obtaining accurate Wannier-function interpolations,defined as an average band distance below20 meV between the DFT and Wannier-interpolated bands,up to 2 eV above the Fermi level for metals or above the conduction band minimum for insulators(and a 100%success rate when including only bands up to 1 eV above these values).展开更多
We introduce an automated,flexible framework(aiida-hubbard)to self-consistently calculate Hubbard U and V parameters from first-principles.By leveraging density-functional perturbation theory,the computation of the Hu...We introduce an automated,flexible framework(aiida-hubbard)to self-consistently calculate Hubbard U and V parameters from first-principles.By leveraging density-functional perturbation theory,the computation of the Hubbard parameters is efficiently parallelized using multiple concurrent and inexpensive primitive cell calculations.Furthermore,the intersite V parameters are defined on-the-fly during the iterative procedure to account for atomic relaxations and diverse coordination environments.We devise a novel,code-agnostic data structure to store Hubbard related information together with the atomistic structure,to enhance the reproducibility of Hubbard-corrected calculations.We demonstrate the scalability and reliability of the framework by computing in high-throughput fashion the self-consistent onsite U and intersite V parameters for 115 Li-containing bulk solids with up to 32 atoms in the unit cell.Our analysis of the Hubbard parameters calculated reveals a significant correlation of the onsite U values on the oxidation state and coordination environment of the atom on which the Hubbard manifold is centered,while intersite V values exhibit a general decay with increasing interatomic distance.We find,e.g.,that the numerical values of U for the 3d orbitals of Fe and Mn can vary up to 3 eV and 6 eV,respectively;their distribution is characterized by typical shifts of about 0.5 eV and 1.0 eV upon change in oxidation state,or local coordination environment.For the intersite V a narrower spread is found,with values ranging between 0.2 eV and 1.6 eV when considering transition metal and oxygen interactions.This framework paves the way for the exploration of redox materials chemistry and high-throughput screening of d and f compounds across diverse research areas,including the discovery and design of novel energy storage materials,as well as other technologically-relevant applications.展开更多
基金support by the NCCR MARVEL,a National Centre of Competence in Research,funded by the Swiss National Science Foundation(Grant number 205602)the Fellowship from the EPFL QSE Center“Many-body neural simulations of quantum materials”(Grant number 10060)supported by a grant from the Swiss National Supercomputing Centre(CSCS)under project ID s1073 and mr33(Piz Daint).
文摘Spin excitations play a fundamental role in understanding magnetic properties of materials,and have significant technological implications for magnonic devices.However,accurately modeling these in transition-metal and rare-earth compounds remains a formidable challenge.Here,we present a fully first-principles approach for calculating spin-wave spectra based on time-dependent(TD)density-functional perturbation theory(DFPT),using nonempirical Hubbard functionals.This approach is implemented in a general noncollinear formulation,enabling the study of magnons in both collinear and noncollinear magnetic systems.Unlike methods that rely on empirical Hubbard U parameters to describe the ground state,and Heisenberg Hamiltonians for describing magnetic excitations,the methodology developed here probes directly the dynamical spin susceptibility(efficiently evaluated with TDDFPT throught the Liouville-Lanczos approach),and treats the linear variation of the Hubbard augmentation(in itself calculated non-empirically)in full at a self-consistent level.Furthermore,the method satisfies the Goldstone condition without requiring empirical rescaling of the exchange-correlation kernel or explicit enforcement of sum rules,in contrast to existing state-of-the-art techniques.We benchmark the novel computational scheme on prototypical transition-metal monoxides NiO and MnO,showing remarkable agreement with experiments and highlighting the fundamental role of these newly implemented Hubbard corrections.The method holds great promise for describing collective spin excitations in complex materials containing localized electronic states.
基金supported by the NCCR MARVEL,a National Center of Competence in Research,funded by the Swiss National Science Foundation(grant number 205602)YJ acknowledge support by the China Scholarship Council program+5 种基金JQ acknowledges support by the HORIZON-RIA 2D-PRINTABLE(proposal number:101135196)this work has received funding from the Swiss State Secretariat for Education,Research and Innovation(SERI)NP and GP acknowledge support by the Swiss National Science Foundation(SNSF)Project Funding(grant 200021E_206190 FISH4DIET)WZ acknowledge support by the National Key Research and Development Program of China(Grant No.2022YFB4400200)National Natural Science Foundation of China(Grant Nos.T2394474,T2394470)the Beijing Outstanding Young Scientist Program and Tencent Foundation through the XPLORER PRIZE.We acknowledge access to Piz Daint or Alps at the Swiss National Supercomputing Center,Switzerland under MARVEL's share with the project ID mr32.We acknowledge fruitful discussions with Edward Baxter Linscott and Miki Bonacci.
文摘Maximally-localized Wannier functions(MLWFs)are widely employed as an essential tool for calculating the physical properties of materials due to their localized nature and computational efficiency.Projectability-disentangled Wannier functions(PDWFs)have recently emerged as a reliable and efficient approach for automatically constructing MLWFs that span both occupied and lowest unoccupied bands.Here,we extend the applicability of PDWFs to magnetic systems and/or those including spin-orbit coupling,and implement such extensions in automated workflows.Furthermore,we enhance the robustness and reliability of constructing PDWFs by defining an extended protocol that automatically expands the projectors manifold,when required,by introducing additional appropriate hydrogenic atomic orbitals.We benchmark our extended protocol on a set of 200 chemically diverse materials,as well as on the 40 systems with the largest band distance obtained with the standard PDWF approach,showing that on our test set the present approach delivers a success rate of over 98%in obtaining accurate Wannier-function interpolations,defined as an average band distance below20 meV between the DFT and Wannier-interpolated bands,up to 2 eV above the Fermi level for metals or above the conduction band minimum for insulators(and a 100%success rate when including only bands up to 1 eV above these values).
基金support from the Deutsche Forschungsgemeinschaft(DFG)under Germany’s Excellence Strategy(EXC 2077,No.390741603,University Allowance,University of Bremen),Lucio Colombi Ciacchi,the host of the“U Bremen Excellence Chair Program”C.M.and E.M acknowledge funding by MaX“Materials Design at the Exascale”,a Center of Excellence co-funded by the European High Performance Computing Joint Undertaking(JU)and participating countries under grant agreement No.101093374+4 种基金M.B.acknowledges funding by the European Centre of Excellence MaX“Materials design at the Exascale”(grant no.824143)and by the SwissTwins project,funded by the Swiss State Secretariat for Education,Research and Innovation(SERI)I.T.acknowledges funding by the Swiss National Science Foundation(grant no.200021-227641)We acknowledge support by the NCCR MARVEL,a National Centre of Competence in Research,funded by the Swiss National Science Foundation(Grant number 205602)This work was supported by a grant from the Swiss National Supercomputing Centre(CSCS)under project ID 465000416(LUMI-G).We thank Julian Geiger,Gabriel Joalland,Austin Zadoks and Timo Reents for useful discussions and feedbacks.
文摘We introduce an automated,flexible framework(aiida-hubbard)to self-consistently calculate Hubbard U and V parameters from first-principles.By leveraging density-functional perturbation theory,the computation of the Hubbard parameters is efficiently parallelized using multiple concurrent and inexpensive primitive cell calculations.Furthermore,the intersite V parameters are defined on-the-fly during the iterative procedure to account for atomic relaxations and diverse coordination environments.We devise a novel,code-agnostic data structure to store Hubbard related information together with the atomistic structure,to enhance the reproducibility of Hubbard-corrected calculations.We demonstrate the scalability and reliability of the framework by computing in high-throughput fashion the self-consistent onsite U and intersite V parameters for 115 Li-containing bulk solids with up to 32 atoms in the unit cell.Our analysis of the Hubbard parameters calculated reveals a significant correlation of the onsite U values on the oxidation state and coordination environment of the atom on which the Hubbard manifold is centered,while intersite V values exhibit a general decay with increasing interatomic distance.We find,e.g.,that the numerical values of U for the 3d orbitals of Fe and Mn can vary up to 3 eV and 6 eV,respectively;their distribution is characterized by typical shifts of about 0.5 eV and 1.0 eV upon change in oxidation state,or local coordination environment.For the intersite V a narrower spread is found,with values ranging between 0.2 eV and 1.6 eV when considering transition metal and oxygen interactions.This framework paves the way for the exploration of redox materials chemistry and high-throughput screening of d and f compounds across diverse research areas,including the discovery and design of novel energy storage materials,as well as other technologically-relevant applications.
