The rare-earth nickelates(RENiO_(3)) exhibit an exceptional complex electronic phase diagram and multiple electronic phase transitions that enrich promising applications in correlated electronic devices beyond convent...The rare-earth nickelates(RENiO_(3)) exhibit an exceptional complex electronic phase diagram and multiple electronic phase transitions that enrich promising applications in correlated electronic devices beyond conventional semiconductors.Nevertheless,the practical applications of RENiO_(3) are challenged by their intrinsic thermodynamic metastability in material synthesis and high material cost.Therefore,developing an economical strategy to achieve the batch synthesis of RENiO_(3) is of vital importance.In this work,we enlarged the synthesis amount of RENiO_(3) up to 20 g per batch using chloride(KCI) assisted molten salt reaction.By optimizing the reaction conditions,the powder of RENiO_(3) with the cubic shape and average size of ~2μm was effectively synthesized,while their phase purity exceeded 95%.In addition,the cost to synthesize RENiO_(3) was further reduced by using rare-earth extraction intermediate products as the raw materials,instead of using the pure rare-earth precursors.It also achieved wide adjustments in the metal-to-insulator-transition temperature from160 to 420 K without significantly reducing the transition sharpness.By enlarging the synthesis amount and the reducing the cost,it paves the way to the device application of RENiO_(3).展开更多
Metastable materials offer a broad and novel platform for the development of next-generation science and technology.Phase engineering including synthesis of materials with unconventional phases and phase transition of...Metastable materials offer a broad and novel platform for the development of next-generation science and technology.Phase engineering including synthesis of materials with unconventional phases and phase transition of metastable materials has been explored in layered materials but has not tackled their anisotropy issue yet.The high anisotropy in layered materials further adds the cost of orientation screening of materials.Herein,we report the effect of Ag doping on facilitating the formation of metastableπ-cubic phase SnS during the solvothermal synthesis process.On this basis,we construct cubic-to-orthorhombic(CTO)samples and elucidate the intrinsic mechanisms of its nearly isotropic thermoelectric properties by characterizing the texturing information and analyzing the valence charge density calculated by density functional theory(DFT).This work demonstrates a convenient approach to synthesize layered materials with isotropic electrical and thermal transport behaviors through a precursor of metastable phase.展开更多
Glassy matter,as metastable materials with long-range structural disorder but short-range order,has attracted considerable research interest over the past decades due to their unique physical,chemical,and mechanical p...Glassy matter,as metastable materials with long-range structural disorder but short-range order,has attracted considerable research interest over the past decades due to their unique physical,chemical,and mechanical properties.However,the intrinsic structural heterogeneity and complex dynamic behaviors of these materials,especially in the supercooled liquid regime and the glassy state,remain central challenges in condensed matter physics and materials science[1,2].展开更多
The driving of vibrational motion by external electric fields is a topic of continued interest,due to the possibility of assessing new or metastable material phases with desirable properties.Here,we combine ab initio ...The driving of vibrational motion by external electric fields is a topic of continued interest,due to the possibility of assessing new or metastable material phases with desirable properties.Here,we combine ab initio molecular dynamics within the electric-dipole approximation with machine-learning neural networks(NNs)to develop a general,efficient and accurate method to perform electric-fielddriven nuclear dynamics for molecules,solids,and liquids.We train equivariant and autodifferentiable NNs for the interatomic potential and the dipole,modifying the model infrastructure to account for the multi-valued nature of the latter in periodic systems.Weshowcase the method by addressing property modifications induced by electric field interactions in a polar liquid and a polar solid from nanosecondlong molecular dynamics simulations with quantum-mechanical accuracy.For liquid water,we present a calculation of the dielectric function in the GHz to THz range and the electrofreezing transition,showing that nuclear quantum effects enhance this phenomenon.For the ferroelectric perovskite LiNbO3,we simulate the ferroelectric to paraelectric phase transition and the nonequilibrium dynamics of driven phonon modes related to the polarization switching mechanisms,showing that a full polarization switch is not achieved in the simulations.展开更多
基金financially supported by the National Key Research and Development Program of China (No. 2021YFA0718900)the National Natural Science Foundation of China (Nos.52073090 and 62074014)+1 种基金the Fundamental Research Funds for the Central Universities (No.FRF-TP-19-023A3Z)Beijing New-star Plan of Science and Technology (No. Z191100001119071)。
文摘The rare-earth nickelates(RENiO_(3)) exhibit an exceptional complex electronic phase diagram and multiple electronic phase transitions that enrich promising applications in correlated electronic devices beyond conventional semiconductors.Nevertheless,the practical applications of RENiO_(3) are challenged by their intrinsic thermodynamic metastability in material synthesis and high material cost.Therefore,developing an economical strategy to achieve the batch synthesis of RENiO_(3) is of vital importance.In this work,we enlarged the synthesis amount of RENiO_(3) up to 20 g per batch using chloride(KCI) assisted molten salt reaction.By optimizing the reaction conditions,the powder of RENiO_(3) with the cubic shape and average size of ~2μm was effectively synthesized,while their phase purity exceeded 95%.In addition,the cost to synthesize RENiO_(3) was further reduced by using rare-earth extraction intermediate products as the raw materials,instead of using the pure rare-earth precursors.It also achieved wide adjustments in the metal-to-insulator-transition temperature from160 to 420 K without significantly reducing the transition sharpness.By enlarging the synthesis amount and the reducing the cost,it paves the way to the device application of RENiO_(3).
基金B.X.and L.W.F.thank financial support from the National Natural Science Foundation of China(Nos.21801133 and 51802146),Jiangsu Specially Appointed Professorship,Innovation and Entrepreneurship Talents in Jiangsu Province and State Key Laboratory of Coordination Chemistry,School of Chemistry and Chemical Engineering,Nanjing University.
文摘Metastable materials offer a broad and novel platform for the development of next-generation science and technology.Phase engineering including synthesis of materials with unconventional phases and phase transition of metastable materials has been explored in layered materials but has not tackled their anisotropy issue yet.The high anisotropy in layered materials further adds the cost of orientation screening of materials.Herein,we report the effect of Ag doping on facilitating the formation of metastableπ-cubic phase SnS during the solvothermal synthesis process.On this basis,we construct cubic-to-orthorhombic(CTO)samples and elucidate the intrinsic mechanisms of its nearly isotropic thermoelectric properties by characterizing the texturing information and analyzing the valence charge density calculated by density functional theory(DFT).This work demonstrates a convenient approach to synthesize layered materials with isotropic electrical and thermal transport behaviors through a precursor of metastable phase.
文摘Glassy matter,as metastable materials with long-range structural disorder but short-range order,has attracted considerable research interest over the past decades due to their unique physical,chemical,and mechanical properties.However,the intrinsic structural heterogeneity and complex dynamic behaviors of these materials,especially in the supercooled liquid regime and the glassy state,remain central challenges in condensed matter physics and materials science[1,2].
基金funding by the European Union (ERC, QUADYMM,101169761).
文摘The driving of vibrational motion by external electric fields is a topic of continued interest,due to the possibility of assessing new or metastable material phases with desirable properties.Here,we combine ab initio molecular dynamics within the electric-dipole approximation with machine-learning neural networks(NNs)to develop a general,efficient and accurate method to perform electric-fielddriven nuclear dynamics for molecules,solids,and liquids.We train equivariant and autodifferentiable NNs for the interatomic potential and the dipole,modifying the model infrastructure to account for the multi-valued nature of the latter in periodic systems.Weshowcase the method by addressing property modifications induced by electric field interactions in a polar liquid and a polar solid from nanosecondlong molecular dynamics simulations with quantum-mechanical accuracy.For liquid water,we present a calculation of the dielectric function in the GHz to THz range and the electrofreezing transition,showing that nuclear quantum effects enhance this phenomenon.For the ferroelectric perovskite LiNbO3,we simulate the ferroelectric to paraelectric phase transition and the nonequilibrium dynamics of driven phonon modes related to the polarization switching mechanisms,showing that a full polarization switch is not achieved in the simulations.
