In this paper, we perform the density functional theory （DFT） -based calculations by the first-principles pseudopo- tential method to investigate the physical properties of the newly discovered superconductor LaRu2A...In this paper, we perform the density functional theory （DFT） -based calculations by the first-principles pseudopo- tential method to investigate the physical properties of the newly discovered superconductor LaRu2As2 for the first time. The optimized structural parameters are in good agreement with the experimental results. The calculated independent elas- tic constants ensure the mechanical stability of the compound. The calculated Cauchy pressure, Pugh＇s ratio as well as Poisson＇s ratio indicate that LaRu2As2 should behave as a ductile material. Due to low Debye temperature, LaRu2As2 may be used as a thermal barrier coating （TBC） material. The new compound should exhibit metallic nature as its valence bands overlap considerably with the conduction bands. LaRu2As2 is expected to be a soft material and easily machinable because of its low hardness value of 6.8 GPa. The multi-band nature is observed in the calculated Fermi surface. A highly anisotropic combination of ionic, covalent and metallic interactions is expected to be in accordance with charge density calculation.展开更多
Here we report the discovery of superconductivity in the ternary LaRu_2As_2 compound. The polycrystalline LaRu_2As_2 samples were synthesized by the conventional solid state reaction method. Powder X-ray diffraction a...Here we report the discovery of superconductivity in the ternary LaRu_2As_2 compound. The polycrystalline LaRu_2As_2 samples were synthesized by the conventional solid state reaction method. Powder X-ray diffraction analysis indicates that LaRu_2As_2 crystallizes in the Th Cr_2Si_2-type crystal structure with the space group I4/mmm(No. 139), and the refined lattice parameters are a = 4.182(6) and c = 10.590(3) . The temperature dependent resistivity measurement shows a clear superconducting transition with the onset T_c(critical temperature) at 7.8 K, and zero resistivity happens at 6.8 K. The upper critical field at zero temperature μ_0H_(c2)(0) was estimated to be 1.6 T from the resistivity measurement. DC magnetic susceptibility measurement shows a bulk superconducting Meissner transition at 7.0 K, and the isothermal magnetization measurement indicates that LaRu_2As_2 is a type-II superconductor.展开更多
文摘In this paper, we perform the density functional theory （DFT） -based calculations by the first-principles pseudopo- tential method to investigate the physical properties of the newly discovered superconductor LaRu2As2 for the first time. The optimized structural parameters are in good agreement with the experimental results. The calculated independent elas- tic constants ensure the mechanical stability of the compound. The calculated Cauchy pressure, Pugh＇s ratio as well as Poisson＇s ratio indicate that LaRu2As2 should behave as a ductile material. Due to low Debye temperature, LaRu2As2 may be used as a thermal barrier coating （TBC） material. The new compound should exhibit metallic nature as its valence bands overlap considerably with the conduction bands. LaRu2As2 is expected to be a soft material and easily machinable because of its low hardness value of 6.8 GPa. The multi-band nature is observed in the calculated Fermi surface. A highly anisotropic combination of ionic, covalent and metallic interactions is expected to be in accordance with charge density calculation.
基金the financial supports from the National Natural Science Foundation of China (11474339)the National Basic Research Program of China (2010CB923000 and 2011CBA00100)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB07020100)
文摘Here we report the discovery of superconductivity in the ternary LaRu_2As_2 compound. The polycrystalline LaRu_2As_2 samples were synthesized by the conventional solid state reaction method. Powder X-ray diffraction analysis indicates that LaRu_2As_2 crystallizes in the Th Cr_2Si_2-type crystal structure with the space group I4/mmm(No. 139), and the refined lattice parameters are a = 4.182(6) and c = 10.590(3) . The temperature dependent resistivity measurement shows a clear superconducting transition with the onset T_c(critical temperature) at 7.8 K, and zero resistivity happens at 6.8 K. The upper critical field at zero temperature μ_0H_(c2)(0) was estimated to be 1.6 T from the resistivity measurement. DC magnetic susceptibility measurement shows a bulk superconducting Meissner transition at 7.0 K, and the isothermal magnetization measurement indicates that LaRu_2As_2 is a type-II superconductor.
