The prediction of chemical synthesis pathways plays a pivotal role in materials science research. Challenges, such as the complexity of synthesis pathways and the lack of comprehensive datasets, currently hinder our a...The prediction of chemical synthesis pathways plays a pivotal role in materials science research. Challenges, such as the complexity of synthesis pathways and the lack of comprehensive datasets, currently hinder our ability to predict these chemical processes accurately. However, recent advancements in generative artificial intelligence(GAI), including automated text generation and question–answering systems, coupled with fine-tuning techniques, have facilitated the deployment of large-scale AI models tailored to specific domains. In this study, we harness the power of the LLaMA2-7B model and enhance it through a learning process that incorporates 13878 pieces of structured material knowledge data.This specialized AI model, named Mat Chat, focuses on predicting inorganic material synthesis pathways. Mat Chat exhibits remarkable proficiency in generating and reasoning with knowledge in materials science. Although Mat Chat requires further refinement to meet the diverse material design needs, this research undeniably highlights its impressive reasoning capabilities and innovative potential in materials science. Mat Chat is now accessible online and open for use, with both the model and its application framework available as open source. This study establishes a robust foundation for collaborative innovation in the integration of generative AI in materials science.展开更多
Our understanding of how photons couple to different degrees of freedom in solids forms the bedrock of ultrafast physics and materials sciences.In this review,the emergent ultrafast dynamics in condensed matter at the...Our understanding of how photons couple to different degrees of freedom in solids forms the bedrock of ultrafast physics and materials sciences.In this review,the emergent ultrafast dynamics in condensed matter at the attosecond timescale have been intensively discussed.In particular,the focus is put on recent developments of attosecond dynamics of charge,exciton,and magnetism.New concepts and indispensable role of interactions among multiple degrees of freedom in solids are highlighted.Applications of attosecond electronic metrology and future prospects toward attosecond dynamics in condensed matter are further discussed.These pioneering studies promise future development of advanced attosecond science and technology such as attosecond lasers,laser medical engineering,and ultrafast electronic devices.展开更多
Employing a comprehensive structure search and high-throughput first-principles calculation method on 1561 compounds,the present study reveals the phase diagram of Lu-H-N.In detail,the formation energy landscape of Lu...Employing a comprehensive structure search and high-throughput first-principles calculation method on 1561 compounds,the present study reveals the phase diagram of Lu-H-N.In detail,the formation energy landscape of Lu-H-N is derived and utilized to assess the thermodynamic stability of each compound that is created via element substitution.The result indicates that there is no stable ternary structure in the Lu-H-N chemical system,however,metastable ternary structures,such as Lu_(20)H_(2)N_(17)(C2/m)and Lu_(2)H_(2)N(P3m1),are observed to have small E_(hull)(<100 meV/atom).It is also found that the energy convex hull of the Lu-H-N system shifts its shape when applying hydrostatic pressure up to 10 GPa,and the external pressure stabilizes a couple of binary phases such as LuN_9 and Lu_(10)H_(21).Additionally,interstitial voids in LuH_(2)are observed,which may explain the formation of Lu_(10)H_(21)and LuH_(3-δ)N_ε.To provide a basis for comparison,x-ray diffraction patterns and electronic structures of some compounds are also presented.展开更多
The Cs V_(3)Sb_(5) kagome lattice holds the promise for manifesting electron correlation,topology and superconductivity.However,by far only three Cs V_(3)Sb_(5)-like kagome materials have been experimentally spotted.W...The Cs V_(3)Sb_(5) kagome lattice holds the promise for manifesting electron correlation,topology and superconductivity.However,by far only three Cs V_(3)Sb_(5)-like kagome materials have been experimentally spotted.We enlarge this family of materials to 1386 compounds via element species substitution,and the further screening process suggests that 28 promising candidates have superior thermodynamic stability,hence they are highly likely to be synthesizable.Moreover,these compounds possess several unique electronic structures,and can be categorized into five non-magnetic and three magnetic groups accordingly.It is our hope that this work can greatly expand the viable phase space of the Cs V_(3)Sb_(5)-like materials for investigating or tuning the novel quantum phenomena in kagome lattice.展开更多
Recent progress in dye-sensitized solar cells （DSC） research is reviewed, focusing on atomic-scale investigations of the interface electronic structures and dynamical processes, including the structure of dye adsorp...Recent progress in dye-sensitized solar cells （DSC） research is reviewed, focusing on atomic-scale investigations of the interface electronic structures and dynamical processes, including the structure of dye adsorption onto Ti02, ultrafast electron injection, hot-electron injection, multiple-exciton generation, and electron-hole recombination. Advanced exper- imental techniques and theoretical approaches are briefly summarized, and then progressive achievements in photovoltaic device optimization based on insights from atomic scale investigations are introduced. Finally, some challenges and oppor- tunities for further improvement of dye solar cells are presented.展开更多
Transition metal dichalcogenides(TMDs),being valley selectively,are an ideal system hosting excitons.Stacking TMDs together to form heterostructure offers an exciting platform to engineer new optical and electronic pr...Transition metal dichalcogenides(TMDs),being valley selectively,are an ideal system hosting excitons.Stacking TMDs together to form heterostructure offers an exciting platform to engineer new optical and electronic properties in solid-state systems.However,due to the limited accuracy and repetitiveness of sample preparation,the effects of interlayer coupling on the electronic and excitonic properties have not been systematically investigated.In this report,we study the photoluminescence spectra of bilayer-bilayer MoS_(2)/WS_(2) heterostructure with a typeⅡband alignment.We demonstrate that thermal annealing can increase interlayer coupling in the van der Waals heterostructures,and after thermally induced band hybridization such heterostructure behaves more like an artificial new solid,rather than just the combination of two individual TMD components.We also carry out experimental and theoretical studies of the electric controllable direct and indirect infrared interlayer excitons in such system.Our study reveals the impact of interlayer coupling on interlayer excitons and will shed light on the understanding and engineering of layer-controlled spin-valley configuration in twisted van der Waals heterostructures.展开更多
Silicene, a newly isolated silicon allotrope with a two-dimensional(2D) honeycomb lattice structure, is predicted to have electronic properties similar to those of graphene, including the existence of signature Dirac ...Silicene, a newly isolated silicon allotrope with a two-dimensional(2D) honeycomb lattice structure, is predicted to have electronic properties similar to those of graphene, including the existence of signature Dirac fermions. Furthermore,the strong spin–orbit interaction of Si atoms potentially makes silicene an experimentally accessible 2D topological insulator. Since 2012, silicene films have been experimentally synthesized on Ag(111) and other substrates, motivating a burst of research on silicene. We and collaborators have employed STM investigations and first principles calculations to intensively study the structure and electronic properties of silicene films on Ag(111), including monolayer, bilayer, and multilayer silicenes, as well as hydrogenation of silicene.展开更多
Light-induced ultrafast spin dynamics in materials is of great importance for developments of spintronics and magnetic storage technology.Recent progresses include ultrafast demagnetization,magnetic switching,and magn...Light-induced ultrafast spin dynamics in materials is of great importance for developments of spintronics and magnetic storage technology.Recent progresses include ultrafast demagnetization,magnetic switching,and magnetic phase transitions,while the ultrafast generation of magnetism is hardly achieved.Here,a strong lightinduced magnetization(up to 0.86μBper formula unit)is identified in non-magnetic monolayer molybdenum disulfide(MoS_(2)).With the state-of-the-art time-dependent density functional theory simulations,we demonstrate that the out-of-plane magnetization can be induced by circularly polarized laser,where chiral phonons play a vital role.The phonons strongly modulate spin-orbital interactions and promote electronic transitions between the two conduction band states,achieving an effective magnetic field~380 T.Our study provides important insights into the ultrafast magnetization and spin-phonon coupling dynamics,facilitating effective light-controlled valleytronics and magnetism.展开更多
The interlayer hybridization(IH)of van der Waals(vdW)materials is thought to be mostly associated with the unignorable interlayer overlaps of wavefunctions(t)in real space.Here,we develop a more fundamental understand...The interlayer hybridization(IH)of van der Waals(vdW)materials is thought to be mostly associated with the unignorable interlayer overlaps of wavefunctions(t)in real space.Here,we develop a more fundamental understanding of IH by introducing a new physical quantity,the IH admixture ratioα.Consequently,an exotic strategy of IH engineering in energy space can be proposed,i.e.,instead of changing t as commonly used,αcan be effectively tuned in energy space by changing the on-site energy difference(2Δ)between neighboring-layer states.In practice,this is feasible via reshaping the electrostatic potential of the surface by deposing a dipolar overlayer,e.g.,crystalline ice.Our first-principles calculations unveil that IH engineering via adjusting 2Δcan greatly tune interlayer optical transitions in transition-metal dichalcogenide bilayers,switch different types of Dirac surface states in Bi_(2)Se_(3)thin films,and control magnetic phase transition of charge density waves in 1H/1T-TaS_(2)bilayers,opening new opportunities to govern the fundamental optoelectronic,topological,and magnetic properties of vdW systems beyond the traditional interlayer distance or twisting engineering.展开更多
Finding viable Kagome lattices is vital for materializing novel phenomena in quantum materials.In this study,we performed element substitutions on CsV_(3)Sb_(5)with space group P 6/mmm,TbMn_(6)Sn_(6)with space group P...Finding viable Kagome lattices is vital for materializing novel phenomena in quantum materials.In this study,we performed element substitutions on CsV_(3)Sb_(5)with space group P 6/mmm,TbMn_(6)Sn_(6)with space group P 6/mmm,and CsV_(6)Sb_(6)with space group R3m,as the parent compounds.Totally 4158 materials were obtained through element substitutions,and these materials were then calculated via density functional theory in high-throughput mode.Afterwards,48 materials were identified with high thermodynamic stability(E_(hull)<5 meV/atom).Furthermore,we compared the thermodynamic stability of three different phases with the same elemental composition and predicted some competing phases that may arise during material synthesis.Finally,by calculating the electronic structures of these materials,we attempted to identify patterns in the electronic structure variations as the elements change.This study provides guidance for discovering promising AM_(3)X_(5)/AM_(6)X_(6)Kagome materials from a vast phase space.展开更多
基金supported by the Informatization Plan of the Chinese Academy of Sciences (Grant No. CASWX2023SF-0101)the Key Research Program of Frontier Sciences, CAS (Grant No. ZDBS-LY-7025)+1 种基金the Youth Innovation Promotion Association CAS (Grant No. 2021167)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB33020000)。
文摘The prediction of chemical synthesis pathways plays a pivotal role in materials science research. Challenges, such as the complexity of synthesis pathways and the lack of comprehensive datasets, currently hinder our ability to predict these chemical processes accurately. However, recent advancements in generative artificial intelligence(GAI), including automated text generation and question–answering systems, coupled with fine-tuning techniques, have facilitated the deployment of large-scale AI models tailored to specific domains. In this study, we harness the power of the LLaMA2-7B model and enhance it through a learning process that incorporates 13878 pieces of structured material knowledge data.This specialized AI model, named Mat Chat, focuses on predicting inorganic material synthesis pathways. Mat Chat exhibits remarkable proficiency in generating and reasoning with knowledge in materials science. Although Mat Chat requires further refinement to meet the diverse material design needs, this research undeniably highlights its impressive reasoning capabilities and innovative potential in materials science. Mat Chat is now accessible online and open for use, with both the model and its application framework available as open source. This study establishes a robust foundation for collaborative innovation in the integration of generative AI in materials science.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFA1400200)the National Natural Science Foundation of China(Grant Nos.12025407,92250303,and 11934003)+3 种基金Chinese Academy of Sciences(Grant Nos.YSBR047 and XDB330301)financial support from the National Science Fund for Distinguished Young Scholars(Grant No.12304096)China Postdoctoral Science Foundation(Grant No.2022TQ0362)Special Research Assistant of Chinese Academy of Sciences Foundation。
文摘Our understanding of how photons couple to different degrees of freedom in solids forms the bedrock of ultrafast physics and materials sciences.In this review,the emergent ultrafast dynamics in condensed matter at the attosecond timescale have been intensively discussed.In particular,the focus is put on recent developments of attosecond dynamics of charge,exciton,and magnetism.New concepts and indispensable role of interactions among multiple degrees of freedom in solids are highlighted.Applications of attosecond electronic metrology and future prospects toward attosecond dynamics in condensed matter are further discussed.These pioneering studies promise future development of advanced attosecond science and technology such as attosecond lasers,laser medical engineering,and ultrafast electronic devices.
基金Chinese Academy of Sciences(Grant Nos.CAS-WX2023SF0101 and XDB33020000)the National Key R&D Program of China(Grant Nos.2021YFA1400200 and 2021YFA0718700)。
文摘Employing a comprehensive structure search and high-throughput first-principles calculation method on 1561 compounds,the present study reveals the phase diagram of Lu-H-N.In detail,the formation energy landscape of Lu-H-N is derived and utilized to assess the thermodynamic stability of each compound that is created via element substitution.The result indicates that there is no stable ternary structure in the Lu-H-N chemical system,however,metastable ternary structures,such as Lu_(20)H_(2)N_(17)(C2/m)and Lu_(2)H_(2)N(P3m1),are observed to have small E_(hull)(<100 meV/atom).It is also found that the energy convex hull of the Lu-H-N system shifts its shape when applying hydrostatic pressure up to 10 GPa,and the external pressure stabilizes a couple of binary phases such as LuN_9 and Lu_(10)H_(21).Additionally,interstitial voids in LuH_(2)are observed,which may explain the formation of Lu_(10)H_(21)and LuH_(3-δ)N_ε.To provide a basis for comparison,x-ray diffraction patterns and electronic structures of some compounds are also presented.
基金the financial support from the Chinese Academy of Sciences(Grant Nos.ZDBS-LY-SLH007,XDB33020000,and CAS-WX2021PY-0102)the National Natural Science Foundation of China(Grant No.12174428)。
文摘The Cs V_(3)Sb_(5) kagome lattice holds the promise for manifesting electron correlation,topology and superconductivity.However,by far only three Cs V_(3)Sb_(5)-like kagome materials have been experimentally spotted.We enlarge this family of materials to 1386 compounds via element species substitution,and the further screening process suggests that 28 promising candidates have superior thermodynamic stability,hence they are highly likely to be synthesizable.Moreover,these compounds possess several unique electronic structures,and can be categorized into five non-magnetic and three magnetic groups accordingly.It is our hope that this work can greatly expand the viable phase space of the Cs V_(3)Sb_(5)-like materials for investigating or tuning the novel quantum phenomena in kagome lattice.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11222431 and 11074287)the National Basic Key Research Program of China(Grant No.2012CB921403)the Hundred-Talent Program of the Chinese Academy of Sciences
文摘Recent progress in dye-sensitized solar cells （DSC） research is reviewed, focusing on atomic-scale investigations of the interface electronic structures and dynamical processes, including the structure of dye adsorption onto Ti02, ultrafast electron injection, hot-electron injection, multiple-exciton generation, and electron-hole recombination. Advanced exper- imental techniques and theoretical approaches are briefly summarized, and then progressive achievements in photovoltaic device optimization based on insights from atomic scale investigations are introduced. Finally, some challenges and oppor- tunities for further improvement of dye solar cells are presented.
基金the National Key Research and Development Program of China(Grant No.2020YFA0309604)the National Natural Science Foundation of China(Grant Nos.11834017,61888102,and 12074413)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB33000000)the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2020B0101340001)the Research Program of Beijing Academy of Quantum Information Sciences(Grant No.Y18G11).
文摘Transition metal dichalcogenides(TMDs),being valley selectively,are an ideal system hosting excitons.Stacking TMDs together to form heterostructure offers an exciting platform to engineer new optical and electronic properties in solid-state systems.However,due to the limited accuracy and repetitiveness of sample preparation,the effects of interlayer coupling on the electronic and excitonic properties have not been systematically investigated.In this report,we study the photoluminescence spectra of bilayer-bilayer MoS_(2)/WS_(2) heterostructure with a typeⅡband alignment.We demonstrate that thermal annealing can increase interlayer coupling in the van der Waals heterostructures,and after thermally induced band hybridization such heterostructure behaves more like an artificial new solid,rather than just the combination of two individual TMD components.We also carry out experimental and theoretical studies of the electric controllable direct and indirect infrared interlayer excitons in such system.Our study reveals the impact of interlayer coupling on interlayer excitons and will shed light on the understanding and engineering of layer-controlled spin-valley configuration in twisted van der Waals heterostructures.
基金supported by the National Natural Science Foundation of China(Grant Nos.11334011,11222431,and 11322431)the National Basic Research Program of China(Grant Nos.2012CB921403,2013CBA01600,and 2012CB921703)+1 种基金the "Strategic Priority Research Program" of the Chinese Academy of Sciencesthe Hundred Talents Program of Institute of Physics,Chinese Academy of Sciences
文摘Silicene, a newly isolated silicon allotrope with a two-dimensional(2D) honeycomb lattice structure, is predicted to have electronic properties similar to those of graphene, including the existence of signature Dirac fermions. Furthermore,the strong spin–orbit interaction of Si atoms potentially makes silicene an experimentally accessible 2D topological insulator. Since 2012, silicene films have been experimentally synthesized on Ag(111) and other substrates, motivating a burst of research on silicene. We and collaborators have employed STM investigations and first principles calculations to intensively study the structure and electronic properties of silicene films on Ag(111), including monolayer, bilayer, and multilayer silicenes, as well as hydrogenation of silicene.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1400201)the National Natural Science Foundation of China(Grant Nos.12025407 and 11934004)Chinese Academy of Sciences(Grant Nos.XDB330301 and YSBR047)。
文摘Light-induced ultrafast spin dynamics in materials is of great importance for developments of spintronics and magnetic storage technology.Recent progresses include ultrafast demagnetization,magnetic switching,and magnetic phase transitions,while the ultrafast generation of magnetism is hardly achieved.Here,a strong lightinduced magnetization(up to 0.86μBper formula unit)is identified in non-magnetic monolayer molybdenum disulfide(MoS_(2)).With the state-of-the-art time-dependent density functional theory simulations,we demonstrate that the out-of-plane magnetization can be induced by circularly polarized laser,where chiral phonons play a vital role.The phonons strongly modulate spin-orbital interactions and promote electronic transitions between the two conduction band states,achieving an effective magnetic field~380 T.Our study provides important insights into the ultrafast magnetization and spin-phonon coupling dynamics,facilitating effective light-controlled valleytronics and magnetism.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1504000)the National Natural Science Foundation of China(Grant Nos.12088101,U2230402)+1 种基金the Tianjin Natural Science Foundation(Grant No.20JCZDJC00750)the Deutsche Forschungsgemeinschaft(DFG)(Grant No.EXC 2077)。
文摘The interlayer hybridization(IH)of van der Waals(vdW)materials is thought to be mostly associated with the unignorable interlayer overlaps of wavefunctions(t)in real space.Here,we develop a more fundamental understanding of IH by introducing a new physical quantity,the IH admixture ratioα.Consequently,an exotic strategy of IH engineering in energy space can be proposed,i.e.,instead of changing t as commonly used,αcan be effectively tuned in energy space by changing the on-site energy difference(2Δ)between neighboring-layer states.In practice,this is feasible via reshaping the electrostatic potential of the surface by deposing a dipolar overlayer,e.g.,crystalline ice.Our first-principles calculations unveil that IH engineering via adjusting 2Δcan greatly tune interlayer optical transitions in transition-metal dichalcogenide bilayers,switch different types of Dirac surface states in Bi_(2)Se_(3)thin films,and control magnetic phase transition of charge density waves in 1H/1T-TaS_(2)bilayers,opening new opportunities to govern the fundamental optoelectronic,topological,and magnetic properties of vdW systems beyond the traditional interlayer distance or twisting engineering.
基金supported by the Chinese Academy of Sciences(Grant Nos.CASWX2023SF-0101,ZDBS-LY-SLH007 and XDB33020000)the National Key R&D Program of China(Grant No.2021YFA0718700)。
文摘Finding viable Kagome lattices is vital for materializing novel phenomena in quantum materials.In this study,we performed element substitutions on CsV_(3)Sb_(5)with space group P 6/mmm,TbMn_(6)Sn_(6)with space group P 6/mmm,and CsV_(6)Sb_(6)with space group R3m,as the parent compounds.Totally 4158 materials were obtained through element substitutions,and these materials were then calculated via density functional theory in high-throughput mode.Afterwards,48 materials were identified with high thermodynamic stability(E_(hull)<5 meV/atom).Furthermore,we compared the thermodynamic stability of three different phases with the same elemental composition and predicted some competing phases that may arise during material synthesis.Finally,by calculating the electronic structures of these materials,we attempted to identify patterns in the electronic structure variations as the elements change.This study provides guidance for discovering promising AM_(3)X_(5)/AM_(6)X_(6)Kagome materials from a vast phase space.
