The Seebeck effect measures the electric potential built up in materials under a temperature gradient.For organic thermoelectric materials,the Seebeck coefficient shows more complicated temperature dependence than con...The Seebeck effect measures the electric potential built up in materials under a temperature gradient.For organic thermoelectric materials,the Seebeck coefficient shows more complicated temperature dependence than conventional systems,with both monotonic increases and nonmonotonic behavior,that is,first increasing and then decreasing.The mechanism behind the phenomenon is intriguing.Through first-principles calculations coupled with the Boltzmann transport equation,we demonstrate typical trends of the Seebeck coefficient with respect to temperature through band structure analysis.展开更多
A new intermetallic compound, Sm3In5, has been synthesized by solid-state reaction of the corresponding pure elements in a welded niobium tube at high temperature. Its crystal structure was established by single-cryst...A new intermetallic compound, Sm3In5, has been synthesized by solid-state reaction of the corresponding pure elements in a welded niobium tube at high temperature. Its crystal structure was established by single-crystal X-ray diffraction. Sm3In5 crystallizes in orthorhombic, space group Cmcm with a = 10.0137（8）, b = 8.1211（7）, c = 10.3858（8） A, V = 844.60（1） A^3, Z = 4, Mr = 1025.15, Dc = 8.062 g/cm^3, μ = 33.791 mm^-1, F（000） = 1724, the final R = 0.0346 and wR = 0.0775 for 533 observed reflections with I 〉 2σ（I）. The structure of Sm3In5 belongs to the modified Pu3Pd5 type. It is isostructural with La3In5 and β-Y3In5, containing one-dimensional （1D） [In5] cluster chains along the c-axis, which are weakly interconnected via In-In bonds （3.345A） to form a three-dimensional （3D） structure. The samarium cations are located at the voids between the 1D [In5] cluster chains. Band structure calculations based on Density Function Theory （DFT） method indicate that Sm3In5 is metallic.展开更多
A new intermetallic compound,YbCu6In6,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-cryst...A new intermetallic compound,YbCu6In6,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-crystal X-ray diffraction.YbCu6In6 crystallizes in tetragonal space group I4/mmm with a = 9.2283（5）,c = 5.4015（4）,V = 460.00（5） 3,Z = 2,Mr = 1243.20,Dc = 8.976 g/cm3,μ = 38.243 mm-1,F（000） = 1076,and the final R = 0.0258 and wR = 0.0602 for 173 observed reflections with I 〉 2σ（I）.The structure of YbCu6In6 belongs to the ThMn12 type.It is isostructural with RECu6In6（RE = Y,Ce,Pr,Nd,Gd,Tb,Dy）,containing one-dimensional（1D） [Cu10In6] cluster chain along the c axis,which is interconnected via sharing the Cu（1） atoms to form a three-dimensional（3D） [Cu6In6] framework with Yb atoms encapsulated in the 1D tunnels along the c axis.Band structure calculations based on Density Functional Theory（DFT） method indicate that YbCu6In6 is metallic.展开更多
A new intermetallic compound,Tb3Co4Sn13,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-cry...A new intermetallic compound,Tb3Co4Sn13,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-crystal X-ray diffraction.Tb3Co4Sn13 crystallizes in cubic,space group Pm3n（No.223） with a = 9.5072（2） ,V = 859.33（3） 3,Z = 2,Mr = 2255.45,Dc = 8.717 g/cm3,μ = 34.369 mm-1,F（000） = 1906,and the final R = 0.0140 and wR = 0.0312 for 199 observed reflections with I〉 2σ（I）.The structure of Tb3Co4Sn13 belongs to the Yb3Rh4Sn13 type.It is isostructural with RE3Co4Sn13（RE = La,Ce）,featuring a 3D [Co4Sn12] framework based on [CoSn6] trigonal prisms.The [CoSn6] trigonal prisms are interconnected via corner-sharing and Sn-Sn bonds to form a 3D [Co4Sn12] framework.The other Sn and Tb atoms are located in the spacers of the 3D framework.Band structure calculations indicate that Tb3Co4Sn13 is metallic.展开更多
EuMg6Sn3.67 has been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction study. EuMg6Sn3.67 crystallizes in he...EuMg6Sn3.67 has been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction study. EuMg6Sn3.67 crystallizes in hexagonal space group P63/m （No. 176） with a = 11.7259（4）, c = 4.5507（2） A, V= 541.88（4）A3 Z = 2, Mr = 734.60, Dc= 4.502 g/cm3, μ = 14.348 mm-1, F（000） = 638, the final R = 0.0128 and wR = 0.0378 for 464 observed reflections with 1 〉 2σ-（1）. EuMg6Sn3.67 is closely related to the Ba2Mg2GeT.33 structure type and features a three-dimensional [Mg6Sn3.67] framework with one-dimensional hexagonal tunnels along the c-axis occupied by the Eu atoms. Electronic structure calculation indicates that the title compound is metallic.展开更多
A new zero-dimensional（0D） thioborate Ba_9B_3GaS_（15） has been discovered by conventional high-temperature solid-state reaction. The compound crystallizes in orthorhombic space group Pbca with a = 8.4759（8）,b = ...A new zero-dimensional（0D） thioborate Ba_9B_3GaS_（15） has been discovered by conventional high-temperature solid-state reaction. The compound crystallizes in orthorhombic space group Pbca with a = 8.4759（8）,b = 22.266（2）,c = 31.426（3） ？,V = 5931（2） ？~3,Z = 8,Mr = 1819.11,Dc = 4.075 g/cm3,μ = 13.684 mm^（-1）,F（000） = 6320,S = 1.034,（Δρ）max = 5.039,（Δρ）min = –5.409 e/？~3,the final R = 0.0362 and w R = 0.1053 for 19243 observed reflections with I 〉 2σ（I）. The structure is constructed by discrete [BS_3]^（3–） trigonal planes and isolated [GaS_4]^（5–） tetrahedra with Ba^（2＋） and isolated S^（2–） filled among them. The UV-Vis-near-IR spectrum reveals a wide band gap of 3.15 eV that agrees with the electronic structure calculation.展开更多
In this paper we present an efficient algorithm for the calculation of photonic crystal band structures and band structures of photonic crystal waveguides.Our method relies on the fact that the dispersion curves of th...In this paper we present an efficient algorithm for the calculation of photonic crystal band structures and band structures of photonic crystal waveguides.Our method relies on the fact that the dispersion curves of the band structure are smooth functions of the quasi-momentum in the one-dimensional Brillouin zone.We show the derivation and computation of the group velocity,the group velocity dispersion,and any higher derivative of the dispersion curves.These derivatives are then employed in a Taylor expansion of the dispersion curves.We control the error of the Taylor expansion with the help of a residual estimate and introduce an adaptive scheme for the selection of nodes in the one-dimensional Brillouin zone at which we solve the underlying eigenvalue problem and compute the derivatives of the dispersion curves.The proposed algorithm is not only advantageous as it decreases the computational effort to compute the band structure but also because it allows for the identification of crossings and anti-crossings of dispersion curves,respectively.This identification is not possible with the standard approach of solving the underlying eigenvalue problem at a discrete set of values of the quasi-momentum without taking the mode parity into account.展开更多
基金supported by the National Natural Science Foundation of China through the project“Science Center for Luminescence from Molecular Aggregates”(SCELMAgrant no.201788102)the Ministry of Science and Technology of China through the National Key R&D Plan(grant no.2017YFA0204501).
文摘The Seebeck effect measures the electric potential built up in materials under a temperature gradient.For organic thermoelectric materials,the Seebeck coefficient shows more complicated temperature dependence than conventional systems,with both monotonic increases and nonmonotonic behavior,that is,first increasing and then decreasing.The mechanism behind the phenomenon is intriguing.Through first-principles calculations coupled with the Boltzmann transport equation,we demonstrate typical trends of the Seebeck coefficient with respect to temperature through band structure analysis.
基金supported by the Youth Science Foundation of Jining University (2009QNKJ07 and 2009QNKJ04)
文摘A new intermetallic compound, Sm3In5, has been synthesized by solid-state reaction of the corresponding pure elements in a welded niobium tube at high temperature. Its crystal structure was established by single-crystal X-ray diffraction. Sm3In5 crystallizes in orthorhombic, space group Cmcm with a = 10.0137（8）, b = 8.1211（7）, c = 10.3858（8） A, V = 844.60（1） A^3, Z = 4, Mr = 1025.15, Dc = 8.062 g/cm^3, μ = 33.791 mm^-1, F（000） = 1724, the final R = 0.0346 and wR = 0.0775 for 533 observed reflections with I 〉 2σ（I）. The structure of Sm3In5 belongs to the modified Pu3Pd5 type. It is isostructural with La3In5 and β-Y3In5, containing one-dimensional （1D） [In5] cluster chains along the c-axis, which are weakly interconnected via In-In bonds （3.345A） to form a three-dimensional （3D） structure. The samarium cations are located at the voids between the 1D [In5] cluster chains. Band structure calculations based on Density Function Theory （DFT） method indicate that Sm3In5 is metallic.
基金Supported by the National Natural Science Foundation of China (No. 21101075)the research foundation for excellent young and middle-aged scientists of Shandong Province (No. BS2011CL009)+2 种基金the Science & Research Program foundation of high education of Shandong Province (No. J11LB52)the Rehearsal National Foundation of Jining University (Nos. 2011YYJJ06 and 2011YYJJ07)the Youths Science Foundation of Jining University (No. 2011QNKJ07)
文摘A new intermetallic compound,YbCu6In6,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-crystal X-ray diffraction.YbCu6In6 crystallizes in tetragonal space group I4/mmm with a = 9.2283（5）,c = 5.4015（4）,V = 460.00（5） 3,Z = 2,Mr = 1243.20,Dc = 8.976 g/cm3,μ = 38.243 mm-1,F（000） = 1076,and the final R = 0.0258 and wR = 0.0602 for 173 observed reflections with I 〉 2σ（I）.The structure of YbCu6In6 belongs to the ThMn12 type.It is isostructural with RECu6In6（RE = Y,Ce,Pr,Nd,Gd,Tb,Dy）,containing one-dimensional（1D） [Cu10In6] cluster chain along the c axis,which is interconnected via sharing the Cu（1） atoms to form a three-dimensional（3D） [Cu6In6] framework with Yb atoms encapsulated in the 1D tunnels along the c axis.Band structure calculations based on Density Functional Theory（DFT） method indicate that YbCu6In6 is metallic.
基金supported by the Youth Science Foundation of Jining University (2009QNKJ07)
文摘A new intermetallic compound,Tb3Co4Sn13,has been synthesized by solid-state reaction of the corresponding pure elements in a welded tantalum tube at high temperature.Its crystal structure was established by single-crystal X-ray diffraction.Tb3Co4Sn13 crystallizes in cubic,space group Pm3n（No.223） with a = 9.5072（2） ,V = 859.33（3） 3,Z = 2,Mr = 2255.45,Dc = 8.717 g/cm3,μ = 34.369 mm-1,F（000） = 1906,and the final R = 0.0140 and wR = 0.0312 for 199 observed reflections with I〉 2σ（I）.The structure of Tb3Co4Sn13 belongs to the Yb3Rh4Sn13 type.It is isostructural with RE3Co4Sn13（RE = La,Ce）,featuring a 3D [Co4Sn12] framework based on [CoSn6] trigonal prisms.The [CoSn6] trigonal prisms are interconnected via corner-sharing and Sn-Sn bonds to form a 3D [Co4Sn12] framework.The other Sn and Tb atoms are located in the spacers of the 3D framework.Band structure calculations indicate that Tb3Co4Sn13 is metallic.
基金supported by the National Natural Science Foundation of China(No.21101075 and 21201081)the research foundation for excellent young and middle-aged scientists of Shandong Province(No.BS2011CL009 and BS2012CL008)+2 种基金the Science & Research Program foundation of high education of Shandong Province(No.J11LB52)the Rehearsal National Foundation of Jining University(Nos.2011YYJJ06 and 2011YYJJ07)the Youths Science Foundation of Jining University(No.2011QNKJ07)
文摘EuMg6Sn3.67 has been synthesized by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction study. EuMg6Sn3.67 crystallizes in hexagonal space group P63/m （No. 176） with a = 11.7259（4）, c = 4.5507（2） A, V= 541.88（4）A3 Z = 2, Mr = 734.60, Dc= 4.502 g/cm3, μ = 14.348 mm-1, F（000） = 638, the final R = 0.0128 and wR = 0.0378 for 464 observed reflections with 1 〉 2σ-（1）. EuMg6Sn3.67 is closely related to the Ba2Mg2GeT.33 structure type and features a three-dimensional [Mg6Sn3.67] framework with one-dimensional hexagonal tunnels along the c-axis occupied by the Eu atoms. Electronic structure calculation indicates that the title compound is metallic.
基金Supported by the National Natural Science Foundation of China(21233009,21225104,91422303,21301175 and 21171168)
文摘A new zero-dimensional（0D） thioborate Ba_9B_3GaS_（15） has been discovered by conventional high-temperature solid-state reaction. The compound crystallizes in orthorhombic space group Pbca with a = 8.4759（8）,b = 22.266（2）,c = 31.426（3） ？,V = 5931（2） ？~3,Z = 8,Mr = 1819.11,Dc = 4.075 g/cm3,μ = 13.684 mm^（-1）,F（000） = 6320,S = 1.034,（Δρ）max = 5.039,（Δρ）min = –5.409 e/？~3,the final R = 0.0362 and w R = 0.1053 for 19243 observed reflections with I 〉 2σ（I）. The structure is constructed by discrete [BS_3]^（3–） trigonal planes and isolated [GaS_4]^（5–） tetrahedra with Ba^（2＋） and isolated S^（2–） filled among them. The UV-Vis-near-IR spectrum reveals a wide band gap of 3.15 eV that agrees with the electronic structure calculation.
文摘In this paper we present an efficient algorithm for the calculation of photonic crystal band structures and band structures of photonic crystal waveguides.Our method relies on the fact that the dispersion curves of the band structure are smooth functions of the quasi-momentum in the one-dimensional Brillouin zone.We show the derivation and computation of the group velocity,the group velocity dispersion,and any higher derivative of the dispersion curves.These derivatives are then employed in a Taylor expansion of the dispersion curves.We control the error of the Taylor expansion with the help of a residual estimate and introduce an adaptive scheme for the selection of nodes in the one-dimensional Brillouin zone at which we solve the underlying eigenvalue problem and compute the derivatives of the dispersion curves.The proposed algorithm is not only advantageous as it decreases the computational effort to compute the band structure but also because it allows for the identification of crossings and anti-crossings of dispersion curves,respectively.This identification is not possible with the standard approach of solving the underlying eigenvalue problem at a discrete set of values of the quasi-momentum without taking the mode parity into account.
