Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse ...Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse of warm dense matter theory is thermal density functional theory(DFT),which,however,suffers from two limitations:(i)its accuracy can depend on the utilized exchange-correlation functional,which has to be approximated,and(ii)it is generally limited to single-electron properties such as the density distribution.Here,we present a new ansatz combining time-dependent DFT results for the dynamic structure factor S_(ee)(q,ω)with static DFT results for the density response.This allows us to estimate the electron-electron static structure factor S_(ee)(q)of warm dense hydrogen with high accuracy over a broad range of densities and temperatures.In addition to its value for the study of warm dense matter,our work opens up new avenues for the future study of electronic correlations exclusively within the framework of DFT for a host of applications.展开更多
The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combin...The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combination of density functional theory and dynamical mean-field theory(DFT+DMFT)to systematically investigate the evolution of electronic correlations in the CsV_(3−x)Cr_(x)Sb_(5)(x=0,1,and 3)series.Our calculations revealed that Cr doping drives the system into a strongly correlated Hund’s metal phase,which is characterized by significant and orbital-dependent enhancements in the quasiparticle effective masses and electronic scattering rates.We trace the origin of this transition to the doping-induced shift from low-to high-spin atomic configurations.This preference for high-spin states,which is promoted by near-half-filling of the Cr-d orbitals,induces a pronounced orbital blocking effect that strengthens the correlations.Our findings establish that Hund’s coupling is the decisive factor governing the rich correlation physics in the CsV_(3−x)Cr_(x)Sb_(5) family,providing a tunable platform for exploring Hund’s metallicity.展开更多
Controlling charge polarity in the semiconducting single-walled carbon nanotubes(CNTs) by substitutional doping is a difficult work due to their extremely strong C–C bonding. In this work, an inner doping strategy is...Controlling charge polarity in the semiconducting single-walled carbon nanotubes(CNTs) by substitutional doping is a difficult work due to their extremely strong C–C bonding. In this work, an inner doping strategy is explored by filling CNTs with one-dimensional(1D)-TM_(6)Te_(6) nanowires to form TM_(6)Te_(6)@CNT-(16,0) 1D van der Waals heterostructures(1D-vd WHs). The systematic first-principles studies on the electronic properties of 1D-vd WHs show that N-type doping CNTs can be formed by charge transfer from TM_(6)Te_(6) nanowires to CNTs, without introducing additional carrier scattering.Particularly, contribution from both T M(e.g., Sc and Y) and Te atoms strengthens the charge transfer. The outside CNTs further confine the dispersion of Te-p orbitals in nanowires that deforms the C-π states at the bottom of the conduction band to quasi sp^(3) hybridization. Our study provides an inner doping strategy that can effectively confine the charge polarity of CNTs and further broaden its applications in some novel nano-devices.展开更多
Calculation of total energies of the electronic ground states of atoms forms the basis for the frozen-core pseudopotentials used in atomistic calculations of much larger scale. Reference values for these energies prov...Calculation of total energies of the electronic ground states of atoms forms the basis for the frozen-core pseudopotentials used in atomistic calculations of much larger scale. Reference values for these energies provide a benchmark for the validation of new software to calculate such potentials. In addition, basic atomic-scale electronic properties such as the (first) ionization energy provide a simple check on the approximation used in the calculation method. We present a comparison of the total energies and ionization energies of atoms Z = 1 - 92 calculated in density functional theory with several levels of exchange-correlation functional and the Hartree-Fock method, comparing ionization energies to experiment. We also investigate the role of relativistic treatment on these energies.展开更多
We present a formalism of charge self-consistent dynamical mean field theory(DMFT)in combination with densityfunctional theory(DFT)within the linear combination of numerical atomic orbitals(LCNAO)framework.We implemen...We present a formalism of charge self-consistent dynamical mean field theory(DMFT)in combination with densityfunctional theory(DFT)within the linear combination of numerical atomic orbitals(LCNAO)framework.We implementedthe charge self-consistent DFT+DMFT formalism by interfacing a full-potential all-electron DFT code with threehybridization expansion-based continuous-time quantum Monte Carlo impurity solvers.The benchmarks on several 3d,4fand 5f strongly correlated electron systems validated our formalism and implementation.Furthermore,within the LCANOframework,our formalism is general and the code architecture is extensible,so it can work as a bridge merging differentLCNAO DFT packages and impurity solvers to do charge self-consistent DFT+DMFT calculations.展开更多
Recently,Lee et al.claimed the experimental discovery of room-temperature ambient-pressure super-conductivity in a Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037).Remarkably,the claimed superconductivi...Recently,Lee et al.claimed the experimental discovery of room-temperature ambient-pressure super-conductivity in a Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037).Remarkably,the claimed superconductivity can persist up to 400 K at ambient pressure.Despite the experimental im-plication,the electronic structure of LK-99 has not yet been studied.Here,we investigate the electronic structures of LK-99 and its parent compound using first-principles calculations,aiming to elucidate the doping effects of Cu.Our results reveal that the parent compound Pb_(10)(PO_(4))_(6)O is an insulator,while Cu doping induces an insulator-metal transition and thus volume contraction.The band structures of LK-99 around the Fermi level are featured by a half-filled flat band and a fully-occupied flat band.These two very flat bands arise from both the 2p orbitals of 1/4-occupied O atoms and the hybridization of the 3d orbitals of Cu with the 2p orbitals of its nearest-neighboring O atoms.Interestingly,we observe four van Hove singularities on these two flat bands.Furthermore,we show that the flat band structures can be tuned by including electronic correlation effects or by doping different elements.We find that among the considered doping elements(Ni,Cu,Zn,Ag,and Au),both Ni and Zn doping result in the gap opening,whereas Au exhibits doping effects more similar to Cu than Ag.Our work establishes a foundation for fu-ture studies to investigate the role of unique electronic structures of LK-99 in its claimed superconducting properties.展开更多
In refs. [1, 2], we proposed a modified electron gas approach(MEGA), with selfinteraction correction (SIC) and spin-parallel correlation correction (SPCC) to the local density approximation (LDA), to estimate correlat...In refs. [1, 2], we proposed a modified electron gas approach(MEGA), with selfinteraction correction (SIC) and spin-parallel correlation correction (SPCC) to the local density approximation (LDA), to estimate correlation energies of many electron systems. It was found that MEGA gives correlation energies for many neutral atoms and molecules with quite low relative errors, 5% and 10% respectively. However, for the highly ionized atoms MEGA cannot give good results. This is due to the different gradient effects of such two cases. Based on the assumption that the Hartree-Fock (HF) limit includes展开更多
For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of ...For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons展开更多
The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlatio...The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,展开更多
基金partially supported by the Center for Advanced Systems Understanding (CASUS), financed by Germany’s Federal Ministry of Education and Research and the Saxon State Government out of the State Budget approved by the Saxon State Parliamentthe European Union’s Just Transition Fund (JTF) within the project Röntgenlaser Optimierung der Laserfusion (ROLF), Contract No. 5086999001, co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament+3 种基金the European Research Council (ERC) under the European Union’s Horizon 2022 Research and Innovation Programme (Grant Agreement No. 101076233, “PREXTREME”)Computations were performed on a Bull Cluster at the Center for Information Services and High-Performance Computing (ZIH) at Technische Universität Dresden and at the Norddeutscher Verbund für Hoch- und Höchstleistungsrechnen (HLRN) under Grant No. mvp00024support by the National Natural Science Foundation of China under Grant No. 12274171support by the Advanced Materials–National Science and Technology Major Project (Grant No. 2024ZD0606900)
文摘Understanding the properties of warm dense hydrogen is of key importance for the modeling of compact astrophysical objects and to understand and further optimize inertial confinement fusion applications.The workhorse of warm dense matter theory is thermal density functional theory(DFT),which,however,suffers from two limitations:(i)its accuracy can depend on the utilized exchange-correlation functional,which has to be approximated,and(ii)it is generally limited to single-electron properties such as the density distribution.Here,we present a new ansatz combining time-dependent DFT results for the dynamic structure factor S_(ee)(q,ω)with static DFT results for the density response.This allows us to estimate the electron-electron static structure factor S_(ee)(q)of warm dense hydrogen with high accuracy over a broad range of densities and temperatures.In addition to its value for the study of warm dense matter,our work opens up new avenues for the future study of electronic correlations exclusively within the framework of DFT for a host of applications.
基金supported by the Development Program of China and the National Key Research (Grant Nos.2023YFA1406200 and 2022YFA1402304)the National Natural Science Foundation of China (Grant Nos.12274169 and 12122405)+3 种基金the Fundamental Research Funds for the Central Universitiesthe Innovation Team for Functional Materials and Devices for Informatics at Anhui Higher Education Institutes (Grant No.2024AH010024)the Natural Science Research Project of Education Department of Anhui Province (Grant No.2025AHGXZK31203)the PHD Research Startup Foundation of Fuyang Normal University (Grant No.2025KYQD0072)。
文摘The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combination of density functional theory and dynamical mean-field theory(DFT+DMFT)to systematically investigate the evolution of electronic correlations in the CsV_(3−x)Cr_(x)Sb_(5)(x=0,1,and 3)series.Our calculations revealed that Cr doping drives the system into a strongly correlated Hund’s metal phase,which is characterized by significant and orbital-dependent enhancements in the quasiparticle effective masses and electronic scattering rates.We trace the origin of this transition to the doping-induced shift from low-to high-spin atomic configurations.This preference for high-spin states,which is promoted by near-half-filling of the Cr-d orbitals,induces a pronounced orbital blocking effect that strengthens the correlations.Our findings establish that Hund’s coupling is the decisive factor governing the rich correlation physics in the CsV_(3−x)Cr_(x)Sb_(5) family,providing a tunable platform for exploring Hund’s metallicity.
基金Project supported by the National Natural Science Foundation of China (Grant No. 92477205)。
文摘Controlling charge polarity in the semiconducting single-walled carbon nanotubes(CNTs) by substitutional doping is a difficult work due to their extremely strong C–C bonding. In this work, an inner doping strategy is explored by filling CNTs with one-dimensional(1D)-TM_(6)Te_(6) nanowires to form TM_(6)Te_(6)@CNT-(16,0) 1D van der Waals heterostructures(1D-vd WHs). The systematic first-principles studies on the electronic properties of 1D-vd WHs show that N-type doping CNTs can be formed by charge transfer from TM_(6)Te_(6) nanowires to CNTs, without introducing additional carrier scattering.Particularly, contribution from both T M(e.g., Sc and Y) and Te atoms strengthens the charge transfer. The outside CNTs further confine the dispersion of Te-p orbitals in nanowires that deforms the C-π states at the bottom of the conduction band to quasi sp^(3) hybridization. Our study provides an inner doping strategy that can effectively confine the charge polarity of CNTs and further broaden its applications in some novel nano-devices.
基金the National Natural Science Foundation of China，the Fundamental Research Funds for the Central Universities，the Open Project of Beijing National Laboratory for Molecular Sciences，the Program for Innovative Research Team of Guizhou Province of China，the University Development Fund of Guizhou Province，the Talent Special Fund of Guizhou Province
文摘Calculation of total energies of the electronic ground states of atoms forms the basis for the frozen-core pseudopotentials used in atomistic calculations of much larger scale. Reference values for these energies provide a benchmark for the validation of new software to calculate such potentials. In addition, basic atomic-scale electronic properties such as the (first) ionization energy provide a simple check on the approximation used in the calculation method. We present a comparison of the total energies and ionization energies of atoms Z = 1 - 92 calculated in density functional theory with several levels of exchange-correlation functional and the Hartree-Fock method, comparing ionization energies to experiment. We also investigate the role of relativistic treatment on these energies.
文摘We present a formalism of charge self-consistent dynamical mean field theory(DMFT)in combination with densityfunctional theory(DFT)within the linear combination of numerical atomic orbitals(LCNAO)framework.We implementedthe charge self-consistent DFT+DMFT formalism by interfacing a full-potential all-electron DFT code with threehybridization expansion-based continuous-time quantum Monte Carlo impurity solvers.The benchmarks on several 3d,4fand 5f strongly correlated electron systems validated our formalism and implementation.Furthermore,within the LCANOframework,our formalism is general and the code architecture is extensible,so it can work as a bridge merging differentLCNAO DFT packages and impurity solvers to do charge self-consistent DFT+DMFT calculations.
文摘Recently,Lee et al.claimed the experimental discovery of room-temperature ambient-pressure super-conductivity in a Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037).Remarkably,the claimed superconductivity can persist up to 400 K at ambient pressure.Despite the experimental im-plication,the electronic structure of LK-99 has not yet been studied.Here,we investigate the electronic structures of LK-99 and its parent compound using first-principles calculations,aiming to elucidate the doping effects of Cu.Our results reveal that the parent compound Pb_(10)(PO_(4))_(6)O is an insulator,while Cu doping induces an insulator-metal transition and thus volume contraction.The band structures of LK-99 around the Fermi level are featured by a half-filled flat band and a fully-occupied flat band.These two very flat bands arise from both the 2p orbitals of 1/4-occupied O atoms and the hybridization of the 3d orbitals of Cu with the 2p orbitals of its nearest-neighboring O atoms.Interestingly,we observe four van Hove singularities on these two flat bands.Furthermore,we show that the flat band structures can be tuned by including electronic correlation effects or by doping different elements.We find that among the considered doping elements(Ni,Cu,Zn,Ag,and Au),both Ni and Zn doping result in the gap opening,whereas Au exhibits doping effects more similar to Cu than Ag.Our work establishes a foundation for fu-ture studies to investigate the role of unique electronic structures of LK-99 in its claimed superconducting properties.
基金the National Natural Science Foundation of Chinathe Special Science Foundation of the State Education Commission of Chinathe Science Foundation of Tsinghua University.
文摘In refs. [1, 2], we proposed a modified electron gas approach(MEGA), with selfinteraction correction (SIC) and spin-parallel correlation correction (SPCC) to the local density approximation (LDA), to estimate correlation energies of many electron systems. It was found that MEGA gives correlation energies for many neutral atoms and molecules with quite low relative errors, 5% and 10% respectively. However, for the highly ionized atoms MEGA cannot give good results. This is due to the different gradient effects of such two cases. Based on the assumption that the Hartree-Fock (HF) limit includes
基金National Natural Science Foundation of ChinaScience Foundation of Tsinghua University.
文摘For the recent twenty years, the ab initio method, being in the leading position in thecomputational quantum chemistry, has made great and convincing success in theprediction of molecular geometries and properties of one-electronic behavior. On theother hand,the energy accuracy it gives is not generally adequate because the molecularorbital theory excessively emphasizes the independence of the motion of the electrons
基金Project supported by the National Natural Science Foundation of Chinathe Special Science Foundation of the State Education Commission of China.
文摘The electron correlation correction is known as the key that dominates the quantitativeaccuracy of the computational quantum chemistry. To search for a new way of lesstime-consuming to estimate the electron correlation energies of large-size molecules,
