利用固相烧结法制备了多铁性材料CaMn7O12多晶块材,断面扫描电子显微镜(SEM)形貌图显示样品的结构致密.使用热释电方法测量CaMn7O12多晶块材的铁电极化,说明材料具有铁电性.测量了CaMn7O12多晶块材的直流和交流输运特性,结合交流阻抗谱...利用固相烧结法制备了多铁性材料CaMn7O12多晶块材,断面扫描电子显微镜(SEM)形貌图显示样品的结构致密.使用热释电方法测量CaMn7O12多晶块材的铁电极化,说明材料具有铁电性.测量了CaMn7O12多晶块材的直流和交流输运特性,结合交流阻抗谱辅助等效回路分析法,对测量数据进行拟合.结果显示CaMn7O12多晶块材的直流和交流输运特性都符合Mott的VRH(variable range hopping)机制,其能带是近似于原子能级的窄带.展开更多
The electronic structure and optical properties of N and Fe codoping Ti02 have been investigated by first-principles calculations based on density functional theory. The calculated results indicate that the stability ...The electronic structure and optical properties of N and Fe codoping Ti02 have been investigated by first-principles calculations based on density functional theory. The calculated results indicate that the stability of N and Fe codoping TiO2 will change at different substitutional sites of N and Fe. The mechanism of band gap narrowing of doping Ti02 is discussed by investigating the density of state. The different substitutional site of N and Fe in codoping TiO2 influences the visible-light absorption. An increased visible-light absorption for doping TiO2 results from the synergistic effect of N and Fe codoping. Therefore, N and Fe codoping may enhance the visible-light photocatalytic activity of TiO2.展开更多
We study the dynamics of a two-mode Bose flubbard model with phase dissipation, based on the master equation. An analytical solution is presented with nonzero asymmetry and phase noise. The effects of asymmetry and ph...We study the dynamics of a two-mode Bose flubbard model with phase dissipation, based on the master equation. An analytical solution is presented with nonzero asymmetry and phase noise. The effects of asymmetry and phase noise play a contrasting role in the dynamics. The asymmetry makes the oscillation fast, while phase noise enlarges the period. The conditions for the cases of fast decay and oscillation are presented. As a possible application, the dynamical evolution of the population for cold atomic gases with synthetic gauge interaction, which can be understood as two-mode dynamics in momentum space, is predicted.展开更多
We analyse surface solitons at the interface between a one-dimensional photonic superlattice and a uniform medium with weak nonlocal nonlinearity. We demonstrate that in deep lattices there exist three kinds of surfac...We analyse surface solitons at the interface between a one-dimensional photonic superlattice and a uniform medium with weak nonlocal nonlinearity. We demonstrate that in deep lattices there exist three kinds of surface solitons when the propagation constant exceeds a critical value, including two on-site solitons and one off-site soliton. These three kinds of surface solitons have unique dynamical properties. If the relative depth of the superlattice is low, there is only one kind of off-site soliton; however, the solitons of this kind can propagate stably, unlike their deep superlattice counterparts. Dipole surface solitons are also investigated, and the stable domain is given.展开更多
Two-dimensional multiferroics,which simultaneously possess ferroelectricity and magnetism in a single phase,are well-known to possess great potential applications in nanoscale memories and spintronics.On the basis of ...Two-dimensional multiferroics,which simultaneously possess ferroelectricity and magnetism in a single phase,are well-known to possess great potential applications in nanoscale memories and spintronics.On the basis of first-principles calculations,a CrNCl_(2) monolayer is reported as an intrinsic multiferroic.The CrNCl_(2) has an antiferromagnetic ground state,with a N´eel temperature of about 88 K,and it exhibits an in-plane spontaneous polarization of 200 pC/m.The magnetic moments of CrNCl_(2) mainly come from the dxy orbital of the Cr cation,but the plane of the dxy orbital is perpendicular to the direction of the ferroelectric polarization,which hardly suppresses the occurrence of ferroelectricity.Therefore,the multiferroic exits in the CrNCl_(2).In addition,like CrNCl_(2),the CrNBr_(2) is an intrinsic multiferroic with antiferromagneticferroelectric ground state while CrNI_(2) is an intrinsic multiferroic with ferromagnetic-ferroelectric ground state.These findings enrich the multiferroics in the two-dimensional system and enable a wide range of applications in nanoscale devices.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
We investigate the ground-state properties and the dynamics of quasi-one-dimensional quantum droplets of binary Bose condensates by employing the Gaussian state theory.We show that there exists three quantum phases fo...We investigate the ground-state properties and the dynamics of quasi-one-dimensional quantum droplets of binary Bose condensates by employing the Gaussian state theory.We show that there exists three quantum phases for the ground states of the droplets,including a coherent state and two macroscopic squeezed states.The phase transition between two macroscopic squeezed states is of the third order;while between the macroscopic squeezed state and the coherent is of a crossover type.As for the dynamics,we find that,by tuning the reduced scattering length to a negative value,a significant fraction of the atoms can be transferred from a coherent state to a macroscopic squeezed state.Our studies open up the possibility of generating macroscopic squeezed states using binary condensates.展开更多
文摘利用固相烧结法制备了多铁性材料CaMn7O12多晶块材,断面扫描电子显微镜(SEM)形貌图显示样品的结构致密.使用热释电方法测量CaMn7O12多晶块材的铁电极化,说明材料具有铁电性.测量了CaMn7O12多晶块材的直流和交流输运特性,结合交流阻抗谱辅助等效回路分析法,对测量数据进行拟合.结果显示CaMn7O12多晶块材的直流和交流输运特性都符合Mott的VRH(variable range hopping)机制,其能带是近似于原子能级的窄带.
基金Project supported by the National Natural Science Foundation of China(No.11005050)the Graduate Innovation Project of Jiangsu Province(No.SJLX_0517)
文摘The electronic structure and optical properties of N and Fe codoping Ti02 have been investigated by first-principles calculations based on density functional theory. The calculated results indicate that the stability of N and Fe codoping TiO2 will change at different substitutional sites of N and Fe. The mechanism of band gap narrowing of doping Ti02 is discussed by investigating the density of state. The different substitutional site of N and Fe in codoping TiO2 influences the visible-light absorption. An increased visible-light absorption for doping TiO2 results from the synergistic effect of N and Fe codoping. Therefore, N and Fe codoping may enhance the visible-light photocatalytic activity of TiO2.
基金Supported by the National Natural Science Foundation of China under Grant No 11374197the Program for Changjiang Scholars and Innovative Research Team in Universities of China under Grant No IRT13076the Hundred Talent Program of Shanxi Province
文摘We study the dynamics of a two-mode Bose flubbard model with phase dissipation, based on the master equation. An analytical solution is presented with nonzero asymmetry and phase noise. The effects of asymmetry and phase noise play a contrasting role in the dynamics. The asymmetry makes the oscillation fast, while phase noise enlarges the period. The conditions for the cases of fast decay and oscillation are presented. As a possible application, the dynamical evolution of the population for cold atomic gases with synthetic gauge interaction, which can be understood as two-mode dynamics in momentum space, is predicted.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10874250, 10674183 and 10804131)National Basic Research Program of China (Grant No 2004CB719804)
文摘We analyse surface solitons at the interface between a one-dimensional photonic superlattice and a uniform medium with weak nonlocal nonlinearity. We demonstrate that in deep lattices there exist three kinds of surface solitons when the propagation constant exceeds a critical value, including two on-site solitons and one off-site soliton. These three kinds of surface solitons have unique dynamical properties. If the relative depth of the superlattice is low, there is only one kind of off-site soliton; however, the solitons of this kind can propagate stably, unlike their deep superlattice counterparts. Dipole surface solitons are also investigated, and the stable domain is given.
基金Project supported by the National Key R&D Program of China(Grant No.2019YFB1704600)the International Cooperation Research Project of Shenzhen(Grant No.GJHZ20180413182004161)+2 种基金the Hubei Provincial Natural Science Foundation of China(Grant No.2020CFA032)the National Natural Science Foundation of China(Grant No.51805395)the China Scholarship Council(Grant No.201906270142).
文摘Two-dimensional multiferroics,which simultaneously possess ferroelectricity and magnetism in a single phase,are well-known to possess great potential applications in nanoscale memories and spintronics.On the basis of first-principles calculations,a CrNCl_(2) monolayer is reported as an intrinsic multiferroic.The CrNCl_(2) has an antiferromagnetic ground state,with a N´eel temperature of about 88 K,and it exhibits an in-plane spontaneous polarization of 200 pC/m.The magnetic moments of CrNCl_(2) mainly come from the dxy orbital of the Cr cation,but the plane of the dxy orbital is perpendicular to the direction of the ferroelectric polarization,which hardly suppresses the occurrence of ferroelectricity.Therefore,the multiferroic exits in the CrNCl_(2).In addition,like CrNCl_(2),the CrNBr_(2) is an intrinsic multiferroic with antiferromagneticferroelectric ground state while CrNI_(2) is an intrinsic multiferroic with ferromagnetic-ferroelectric ground state.These findings enrich the multiferroics in the two-dimensional system and enable a wide range of applications in nanoscale devices.
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supported by NSFC(Grants No.12135018,No.11974363,and No.12047503)NKRDPC(Grant No.2021YFA0718304)+1 种基金the Strategic Priority Research Program of CAS(Grant No.XDB28000000)support by the Youth Innovation Promotion Association CAS
文摘We investigate the ground-state properties and the dynamics of quasi-one-dimensional quantum droplets of binary Bose condensates by employing the Gaussian state theory.We show that there exists three quantum phases for the ground states of the droplets,including a coherent state and two macroscopic squeezed states.The phase transition between two macroscopic squeezed states is of the third order;while between the macroscopic squeezed state and the coherent is of a crossover type.As for the dynamics,we find that,by tuning the reduced scattering length to a negative value,a significant fraction of the atoms can be transferred from a coherent state to a macroscopic squeezed state.Our studies open up the possibility of generating macroscopic squeezed states using binary condensates.
