A theory of superconductivity based on Bose-Einstein statistics was proposed,which can lead to a formula for T(critical temperature)similar to that of BCS theory,and provide a possible explanation for the complexity o...A theory of superconductivity based on Bose-Einstein statistics was proposed,which can lead to a formula for T(critical temperature)similar to that of BCS theory,and provide a possible explanation for the complexity of isotope effect and the normal state energy gap in copper-oxides.We proceeded from a 3-dimensional harmonic oscillator model to equivalent the superconducting state to a two-dimensional Bose-Einstein condensate bound longitudinally,and pointed out the application conditions of the theory.Under this scheme,we analyzed some typical structural features in copper oxides that favor the production of high-temperature superconductivity.We also discovered that combining this theory with an alternative mechanism-strong coupling to local spin configurations-provided some useful hints for exploring new superconducting materials.In addition,we pointed out a possible link between the phenomenon of superconductivity and magnetostriction,then we proposed some combinations of elements as possible candidates for high temperature superconducting materials based on those analysis.展开更多
Development of piezoelectric materials through chemical design meets the requirement of the nextgeneration electronic devices,yet the sensitive piezoelectricity to both chemical components and operational environment ...Development of piezoelectric materials through chemical design meets the requirement of the nextgeneration electronic devices,yet the sensitive piezoelectricity to both chemical components and operational environment call for the trial and error method during material preparation.In order to give an atomic-level understanding about functional unit and assist the chemical design,deep learning was applied to train a novelmodel based on themost popular BaTiO3 system,as a case study in this work.Through training the atomic force field of calcium and stannum doped solid-solution with Deep Potential method,3D structure of chemical distribution and corresponding polarization configuration can be constructed for different compositions under different temperatures,which exhibits a high degree of consistency with the local structure quantitatively analyzed from HAADF STEM and reverse Monte Carlo refinement of neutron total scattering data,especially for the critical composition with ultrahigh piezoelectricity of d33~860 pC/N.Systemic analysis reveals that variations in chemical bond length among various elements with oxygen elements are the primary factors influencing ferroelectric activity and leading to structural evolution.The results and methodology can facilitate the discovery of new ferroelectrics and the design of high-performance piezo/ferroelectrics with atomic-level insights.展开更多
文摘A theory of superconductivity based on Bose-Einstein statistics was proposed,which can lead to a formula for T(critical temperature)similar to that of BCS theory,and provide a possible explanation for the complexity of isotope effect and the normal state energy gap in copper-oxides.We proceeded from a 3-dimensional harmonic oscillator model to equivalent the superconducting state to a two-dimensional Bose-Einstein condensate bound longitudinally,and pointed out the application conditions of the theory.Under this scheme,we analyzed some typical structural features in copper oxides that favor the production of high-temperature superconductivity.We also discovered that combining this theory with an alternative mechanism-strong coupling to local spin configurations-provided some useful hints for exploring new superconducting materials.In addition,we pointed out a possible link between the phenomenon of superconductivity and magnetostriction,then we proposed some combinations of elements as possible candidates for high temperature superconducting materials based on those analysis.
基金supported by the National Key R&D Program of China(Grant No.2023YFB3508200)the Outstanding Young Scientist Program of Beijing Colleges and Universities(JWZQ20240101015)the National Natural Science Foundation of China(Grant Nos.92370104,22235002 and 52172181).We acknowledge the computational resource from Beijing PARATERA Tech Corp,LTD.
文摘Development of piezoelectric materials through chemical design meets the requirement of the nextgeneration electronic devices,yet the sensitive piezoelectricity to both chemical components and operational environment call for the trial and error method during material preparation.In order to give an atomic-level understanding about functional unit and assist the chemical design,deep learning was applied to train a novelmodel based on themost popular BaTiO3 system,as a case study in this work.Through training the atomic force field of calcium and stannum doped solid-solution with Deep Potential method,3D structure of chemical distribution and corresponding polarization configuration can be constructed for different compositions under different temperatures,which exhibits a high degree of consistency with the local structure quantitatively analyzed from HAADF STEM and reverse Monte Carlo refinement of neutron total scattering data,especially for the critical composition with ultrahigh piezoelectricity of d33~860 pC/N.Systemic analysis reveals that variations in chemical bond length among various elements with oxygen elements are the primary factors influencing ferroelectric activity and leading to structural evolution.The results and methodology can facilitate the discovery of new ferroelectrics and the design of high-performance piezo/ferroelectrics with atomic-level insights.
