The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mecha...The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mechanism of high temperature superconductivity.A natural starting point is to elucidate the basic electronic structure of the parent compound.Here we report comprehensive high resolution angle-resolved photoemission measurements on Ca_2CuO_2Cl_2,a Mott insulator and a prototypical parent compound of the cuprates.Multiple underl.ying Fermi surface sheets are revealed for the first time.The high energy waterfall-like band dispersions exhibit different behaviors near the nodal and antinodal regions.Two distinct energy scales are identified：a d-wave-like low energy peak dispersion and a nearly isotropic lower Hubbard band gap.These observations provide new information of the electronic structure of the cuprate parent compound,which is important for understanding the anomalous physical properties and superconductivity mechanism of the high temperature cuprate superconductors.展开更多
Amino 4,6 dimethoxypyrimidine(AMP) was synthesized using benzyltriethyl ammonium chloride(BTEA) as a catalyst in yield of 87 5%. A solid complex Co(AMP) 2Cl 2 was obtained by refluxing AMP with CoCl 2 in ethanol. The ...Amino 4,6 dimethoxypyrimidine(AMP) was synthesized using benzyltriethyl ammonium chloride(BTEA) as a catalyst in yield of 87 5%. A solid complex Co(AMP) 2Cl 2 was obtained by refluxing AMP with CoCl 2 in ethanol. The composition of the complex was determined by chemical and elemental analyses. The structure of the complex and sp 3 d 2 of the hybridization type of Co 2+ were estimated by IR, XPS and 1H NMR.展开更多
基金Supported by the National Key Research and Development Program of China(2016YFA0300300)the National Natural Science Foundation of China(11334010 and 11534007)+1 种基金the National Basic Research Program of China(2015CB921000)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB07020300)
文摘The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mechanism of high temperature superconductivity.A natural starting point is to elucidate the basic electronic structure of the parent compound.Here we report comprehensive high resolution angle-resolved photoemission measurements on Ca_2CuO_2Cl_2,a Mott insulator and a prototypical parent compound of the cuprates.Multiple underl.ying Fermi surface sheets are revealed for the first time.The high energy waterfall-like band dispersions exhibit different behaviors near the nodal and antinodal regions.Two distinct energy scales are identified：a d-wave-like low energy peak dispersion and a nearly isotropic lower Hubbard band gap.These observations provide new information of the electronic structure of the cuprate parent compound,which is important for understanding the anomalous physical properties and superconductivity mechanism of the high temperature cuprate superconductors.
文摘Amino 4,6 dimethoxypyrimidine(AMP) was synthesized using benzyltriethyl ammonium chloride(BTEA) as a catalyst in yield of 87 5%. A solid complex Co(AMP) 2Cl 2 was obtained by refluxing AMP with CoCl 2 in ethanol. The composition of the complex was determined by chemical and elemental analyses. The structure of the complex and sp 3 d 2 of the hybridization type of Co 2+ were estimated by IR, XPS and 1H NMR.
