The constitution of the binary system Ir-B has been established between 10 and 70 at.% boron for temperatures above 700°C based on differential scanning calorimetry, electron probe microanalysis, and isothermal l...The constitution of the binary system Ir-B has been established between 10 and 70 at.% boron for temperatures above 700°C based on differential scanning calorimetry, electron probe microanalysis, and isothermal low temperature annealing experiments(≤1000°C). Four binary phases have been found, namely Ir4B5+x, Ir5B4+x and the high and low temperature modification of Ir4B3-x. X-ray structure analyses were performed on single crystals of Ir4B5+x(x = 0, Ir4B5 type; space group C2/m; a = 1.05200(2), b = 0.289564(6) and c = 0.60958(1) nm, β = 91.156(2)°), Ir5B4+x(x=0, Ir5B4 type; space group I41/a; a = 0.62777(1) and b = 1.02599(2) nm) and on the low temperature modification of Ir4B3-x(x=0, Ir B0.9 type; space group Cmc21; a = 0.27728(1), b = 0.75742(2) and c = 0.73152(2) nm). The high temperature modification of Ir4B3-x(WC type; space group P6-m2; a = 0.28137(5) and c = 0.2828(1) nm) has been confirmed by X-ray powder diffraction. By means of the first-principle calculations, in combination with the evolutionary structural search algorithm, the compositions, structures and enthalpies of the Ir-B system have been investigated theoretically. Confirming the experimental observations on Ir4B5, Ir5B4 and Ir4B3, we have investigated several metastable phases at other stoichiometries, such as Ir B, Ir B2 and Ir3B2. We also proposed three thermodynamically and dynamically stable new structures of o F28-Ir4B3, o C8-Ir B and m C10-Ir3B2, which may be synthesized under certain conditions.展开更多
Second-order nonlinear optical(NLO)crystalline materials are fundamentally and technologically important for their ability to double or triple the frequency of lasers.This article provides a brief review of the atom r...Second-order nonlinear optical(NLO)crystalline materials are fundamentally and technologically important for their ability to double or triple the frequency of lasers.This article provides a brief review of the atom response theory(ART)of NLO responses recently developed on the basis of the partial response functional method.The ART analysis enables one to quantitatively evaluate the contributions of individual constituent atoms to the second harmonic generation(SHG)response of a NLO crystal material on the basis of first principles DFT calculations.The general partitioning principles developed in our recent work provide the conceptual foundation for determining the functional motifs of SHG responses.In this mini review we will focus on the concepts and principles as well as on applications with examples.Some practically important empirical rules resulting from the ART studies will also be reviewed.展开更多
基金supported by Austrian Science Fund FWF under P22295partially supported by the ‘Hundred Talents Project’ of Chinese Academy of Sciences+1 种基金the Key Research Program of Chinese Academy of Sciences (KGZD-EW-T06)the National Natural Science Foundation of China (NSFC) (51074188 and 51474202)
文摘The constitution of the binary system Ir-B has been established between 10 and 70 at.% boron for temperatures above 700°C based on differential scanning calorimetry, electron probe microanalysis, and isothermal low temperature annealing experiments(≤1000°C). Four binary phases have been found, namely Ir4B5+x, Ir5B4+x and the high and low temperature modification of Ir4B3-x. X-ray structure analyses were performed on single crystals of Ir4B5+x(x = 0, Ir4B5 type; space group C2/m; a = 1.05200(2), b = 0.289564(6) and c = 0.60958(1) nm, β = 91.156(2)°), Ir5B4+x(x=0, Ir5B4 type; space group I41/a; a = 0.62777(1) and b = 1.02599(2) nm) and on the low temperature modification of Ir4B3-x(x=0, Ir B0.9 type; space group Cmc21; a = 0.27728(1), b = 0.75742(2) and c = 0.73152(2) nm). The high temperature modification of Ir4B3-x(WC type; space group P6-m2; a = 0.28137(5) and c = 0.2828(1) nm) has been confirmed by X-ray powder diffraction. By means of the first-principle calculations, in combination with the evolutionary structural search algorithm, the compositions, structures and enthalpies of the Ir-B system have been investigated theoretically. Confirming the experimental observations on Ir4B5, Ir5B4 and Ir4B3, we have investigated several metastable phases at other stoichiometries, such as Ir B, Ir B2 and Ir3B2. We also proposed three thermodynamically and dynamically stable new structures of o F28-Ir4B3, o C8-Ir B and m C10-Ir3B2, which may be synthesized under certain conditions.
基金financially supported by the National Natural Science Foundation(NSF)of China(21921001,21703251,22031009,22075282,61874122)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB20000000)+2 种基金the National Key Research and Development Program of China(2016YFB0701001)the NSF of Fujian Province(2019J05151,2019J01121)the Youth Innovation Promotion of CAS(2019302)。
文摘Second-order nonlinear optical(NLO)crystalline materials are fundamentally and technologically important for their ability to double or triple the frequency of lasers.This article provides a brief review of the atom response theory(ART)of NLO responses recently developed on the basis of the partial response functional method.The ART analysis enables one to quantitatively evaluate the contributions of individual constituent atoms to the second harmonic generation(SHG)response of a NLO crystal material on the basis of first principles DFT calculations.The general partitioning principles developed in our recent work provide the conceptual foundation for determining the functional motifs of SHG responses.In this mini review we will focus on the concepts and principles as well as on applications with examples.Some practically important empirical rules resulting from the ART studies will also be reviewed.
