Single-layer superconductors[1]have been the subject of considerable interests as they are ideal systems for the fundamental understanding of two-dimensional(2D)physics and for device applications.A few singlelayer su...Single-layer superconductors[1]have been the subject of considerable interests as they are ideal systems for the fundamental understanding of two-dimensional(2D)physics and for device applications.A few singlelayer superconductors are experimentally achieved(e.g.,FeSe,MoS2,and NbSe2[2-4]in the field where either charge doping or tensile strain is often required to promote the superconductivity.展开更多
This paper studies the effects of He atom on the spin-polarized electronic properties of nickel under pressures using ab initio pseudopotential plan-wave method. Under high pressures, the compound of NiHeo.25 can exis...This paper studies the effects of He atom on the spin-polarized electronic properties of nickel under pressures using ab initio pseudopotential plan-wave method. Under high pressures, the compound of NiHeo.25 can exist and helium- bubble can not create in Ni. A pressure-induced ferromagnetic to paramagnetic phase transition has been predicted in NiHeo.25 at about 218 GPa. It is found that under pressures, the magnetic property of Ni atoms is more strongly affected by He atom than by H atom and that the behaviour of He atom in Ni are completely different from that of H atom, like the bonding characteristics and the electron transfer.展开更多
Semiconductivity and superconductivity are remarkable quantum phenomena that have immense impact on science and technology,and materials that can be tuned,usually by pressure or doping,to host both types of quantum st...Semiconductivity and superconductivity are remarkable quantum phenomena that have immense impact on science and technology,and materials that can be tuned,usually by pressure or doping,to host both types of quantum states are of great fundamental and practical significance.Here we show by first-principles calculations a distinct route for tuning semiconductors into superconductors by diverse large-range elastic shear strains,as demonstrated in exemplary cases of silicon and silicon carbide.Analysis of strain driven evolution of bonding structure,electronic states,lattice vibration,and electron-phonon coupling unveils robust pervading deformation induced mechanisms auspicious for modulating semiconducting and superconducting states under versatile material conditions.This finding opens vast untapped structural configurations for rational exploration of tunable emergence and transition of these intricate quantum phenomena in a broad range of materials.展开更多
The equilibrium lattice constant, the cohesive energy and the electronic properties of light metal hydrides LiXH3 and XLiH3 （X = Be, B or C） with perovskite lattice structures have been investigated by using the pse...The equilibrium lattice constant, the cohesive energy and the electronic properties of light metal hydrides LiXH3 and XLiH3 （X = Be, B or C） with perovskite lattice structures have been investigated by using the pseudopotential plane-wave method. Large energy gap of LiBeH3 indicates that it is insulating, but other investigated hydrides are metallic. The pressure-induced metallization of LiBeH3 is found at about 120 GPa, which is attributed to the increase of Be-p electrons with pressure. The electronegativity of the p electrons of X atom is responsible for the metallicity of the investigated LiXH3 hydrides, but the electronegativity of the s electrons of X atom plays an important role in the metallicity of the investigated XLiH3 hydrides. In order to deeply understand the investigated hydrides, their optical properties have also been investigated. The optical absorption of either LiBeH3 or BeLiH3 has a strong peak at about 5 eV, showing that their optical responses are qualitatively similar. It is also found that the optical responses of other investigated hydrides are stronger than those of LiBeH3 and BeLiH3 in lower energy ranges, especially in the case of CLiH3.展开更多
We perform an ab initio study on the electronic structure and charge density of the c-oxygen under high pressure, which is obtained by powder x-ray diffraction experiment recently. Our results show that the hybridizat...We perform an ab initio study on the electronic structure and charge density of the c-oxygen under high pressure, which is obtained by powder x-ray diffraction experiment recently. Our results show that the hybridization among the σg^＊, πu and πg^＊ bands in the e-oxygen are not significant even at megabar pressure. Pressure-induced metallization occurs due to the band overlapping near the Fermi level at about 50 GPa. A new network along the b-axis is formed and the 08 characteristic in the e phase disappears above 50 GPa even though the symmetry remains unchanged.展开更多
文摘Single-layer superconductors[1]have been the subject of considerable interests as they are ideal systems for the fundamental understanding of two-dimensional(2D)physics and for device applications.A few singlelayer superconductors are experimentally achieved(e.g.,FeSe,MoS2,and NbSe2[2-4]in the field where either charge doping or tensile strain is often required to promote the superconductivity.
基金supported by the National Natural Science Foundation of China (Grants Nos 10574053 and 10674053)2004 NCET and 2003 EYTP of Ministry of Education of China,National Basic Research Program of China (Grant Nos 2005CB724400 and 2001CB711201)+2 种基金the Cultivation Fund of the Key Scientific and Technical Innovation Project (Grant No 2004-295)2007 Cheung Kong Scholars Programme of ChinaChangjiang Scholar and Innovative Research Team in University of China (Grant NoIRT0625)
文摘This paper studies the effects of He atom on the spin-polarized electronic properties of nickel under pressures using ab initio pseudopotential plan-wave method. Under high pressures, the compound of NiHeo.25 can exist and helium- bubble can not create in Ni. A pressure-induced ferromagnetic to paramagnetic phase transition has been predicted in NiHeo.25 at about 218 GPa. It is found that under pressures, the magnetic property of Ni atoms is more strongly affected by He atom than by H atom and that the behaviour of He atom in Ni are completely different from that of H atom, like the bonding characteristics and the electron transfer.
基金the National Key Research and Development Program of China(Grant No.2018YFA0703400)the National Natural Science Foundation of China(Grant Nos.12074140 and 12034009)+1 种基金the China Postdoctoral Science Foundation(Grant No.2020M681031)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)。
文摘Semiconductivity and superconductivity are remarkable quantum phenomena that have immense impact on science and technology,and materials that can be tuned,usually by pressure or doping,to host both types of quantum states are of great fundamental and practical significance.Here we show by first-principles calculations a distinct route for tuning semiconductors into superconductors by diverse large-range elastic shear strains,as demonstrated in exemplary cases of silicon and silicon carbide.Analysis of strain driven evolution of bonding structure,electronic states,lattice vibration,and electron-phonon coupling unveils robust pervading deformation induced mechanisms auspicious for modulating semiconducting and superconducting states under versatile material conditions.This finding opens vast untapped structural configurations for rational exploration of tunable emergence and transition of these intricate quantum phenomena in a broad range of materials.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10574053 and 10674053, the New Century Excellent Talent Project （NCET） of the Ministry of Education of China under Grant No 20052, the Excellent Young University Teacher＇s Fund from the Ministry of Education of China under Grant No 2003355, the National Key Basic Research Programme of China under Grant No 2005CB724400, the Cultivation Fund of the Key Scientific and Technical Innovation Project of the Ministry of Education of China under Grant No 2004-295, and the 2007 Cheung Kong Scholars Programme of China.
文摘水晶结构和 delta-O-2 阶段和 epsilon-O-8 阶段的光性质被使用 ab initio 调查了假潜在的飞机波浪方法。阶段转变具有有从反的一个不连续的容量的变化的第一份订单，这被发现铁磁性的 delta-O-2 阶段到无磁性的 epsilon-O-8 阶段，与试验性的调查结果一致。精力乐队计算证明直接乐队差距在阶段转变以后变成间接乐队差距。在光性质的明显的变化能被用于从 delta-O-2 识别阶段转变到 epsilon-O-8。
基金Supported by the National Natural Science Foundation of China under Grant No 10574053, the Ministry of Education of China under Grant Nos 2004 NCET and 2003 EYTP, and the National Key Basic Research Programme of China under Grant No 2005CB724400.
基金Supported by the National Natural Science Foundation of China under No 10676011, the National Key Basic Research Programme of China under Nos 2005CB724400 and 2001CB711201, the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20050183062, the SRF for R0CS of SEM, the Programme for 2005 New Century Excellent Talents in University, and the2006 Project for Scientific and Technical Development of Jilin Province.
文摘菱形的 CaC6 的格子动力学作为压力的功能被学习用密度与低超导的转变温度探查它的高压力阶段功能的班机反应理论。在 CaC6 的导致压力的阶段转变对弄软可归因横向声学(TA ) 在地区边界 X 的声子模式(0.5， 0.0,0.5 ) 点。高压力阶段然后被在提供相应于 TA (X) 的不稳定的模式的特徵向量的原子排水量的超级房间执行充分结构的优化探索。高压的阶段被预言是有空间组 P21/m 的一个单斜晶的单位房间。
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10574053 and 10674053)the 2004 NCET and 2003 EYTP of MOE of China, the National Basic Research Program of China (Grant Nos 2005CB724400 and 2001CB711201)the Cultivation Fund of the Key Scientific and Technical Innovation Project, China (Grant No 2004-295)
文摘The equilibrium lattice constant, the cohesive energy and the electronic properties of light metal hydrides LiXH3 and XLiH3 （X = Be, B or C） with perovskite lattice structures have been investigated by using the pseudopotential plane-wave method. Large energy gap of LiBeH3 indicates that it is insulating, but other investigated hydrides are metallic. The pressure-induced metallization of LiBeH3 is found at about 120 GPa, which is attributed to the increase of Be-p electrons with pressure. The electronegativity of the p electrons of X atom is responsible for the metallicity of the investigated LiXH3 hydrides, but the electronegativity of the s electrons of X atom plays an important role in the metallicity of the investigated XLiH3 hydrides. In order to deeply understand the investigated hydrides, their optical properties have also been investigated. The optical absorption of either LiBeH3 or BeLiH3 has a strong peak at about 5 eV, showing that their optical responses are qualitatively similar. It is also found that the optical responses of other investigated hydrides are stronger than those of LiBeH3 and BeLiH3 in lower energy ranges, especially in the case of CLiH3.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10574053 and 10674053, 2004 NCET and 2003 EYTP of MOE of China, the National Basic Research Programme of China under No 2005CB724400, and the Cultivation Fund of the Key Scientific and Technical Innovation Project under Grant No 2004-295.
文摘We perform an ab initio study on the electronic structure and charge density of the c-oxygen under high pressure, which is obtained by powder x-ray diffraction experiment recently. Our results show that the hybridization among the σg^＊, πu and πg^＊ bands in the e-oxygen are not significant even at megabar pressure. Pressure-induced metallization occurs due to the band overlapping near the Fermi level at about 50 GPa. A new network along the b-axis is formed and the 08 characteristic in the e phase disappears above 50 GPa even though the symmetry remains unchanged.
