We perform 31p nuclear magnetic resonance （NMR） measurements on a single crystal of RuP. The anomalies in resistivity at about TA = 270 K and TB = 330 K indicate that two phase transitions occur. The line shape of a...We perform 31p nuclear magnetic resonance （NMR） measurements on a single crystal of RuP. The anomalies in resistivity at about TA = 270 K and TB = 330 K indicate that two phase transitions occur. The line shape of alp NMR spectra in different temperature ranges is attributed to the charge density distribution. The Knight shift and spin-lattice relaxation rate 1/T1T are measured from 1OK to 30OK. At about TA = 270K, they both decrease abruptly with the temperature reduction, which reveals the gap-opening behavior. Well below TA, they act like the case of normal metal. Charge-density-wave phase transition is proposed to interpret the transition occurring at about TA.展开更多
Spectral sensitization micromechanism of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr microcrystals with different dye concentrations is studied by using picosecond time-resolved fluorescence spectr...Spectral sensitization micromechanism of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr microcrystals with different dye concentrations is studied by using picosecond time-resolved fluorescence spectroscopy, and the dependences of electron transfer and spectral efficiency sensitization on different conditions are analysed in detail, With the steady spectroscopy, the wavelengths of absorption and fluorescence of J-aggregate adsorbed on AgBr microcrystals are found to shift to red relative to dye monomer. The spectrum of fluorescence has a red shift relative to the absorption peak. With the time-resolved fluorescence spectroscopy, the fluorescence decay curves of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr grains are found to be fitted well by a double-exponential decay function. The fitting curves consist of a fast and a slow component. Because of the large amplitude of the fast component, this fast decay should be attributable mainly to the electron transfer from J-aggregate of dye to a conduction band of AgBr.展开更多
^(75)As nuclear magnetic resonance(NMR)was measured for Ba(Fe_(1-x)Ni_(x))_(2)As_(2)single crystals with x=0.05 and x=0.1 under 0 and 1.5GPa,respectively.For the optimal doped sample with x=0.05,the superconducting tr...^(75)As nuclear magnetic resonance(NMR)was measured for Ba(Fe_(1-x)Ni_(x))_(2)As_(2)single crystals with x=0.05 and x=0.1 under 0 and 1.5GPa,respectively.For the optimal doped sample with x=0.05,the superconducting transition temperature,Tc,is strongly suppressed from 18 to 5 K,while for the over-doped sample with x=0.1,it is turned from a superconducting ground state to a disordered paramagnetic state under 1.5 GPa.Our experimental results show that the antiferromagnetic spin fluctuations,as well as Tc,are suppressed.The experimental results can be explained with the two-band model.As a result,the electronic band is shifted downwards with an increase in pressure,and the electrons become the dominant carriers in the system.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11025422the National Basic Research Program of China under Grant Nos 2011CB921700 and 2015CB921300the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07020200
文摘We perform 31p nuclear magnetic resonance （NMR） measurements on a single crystal of RuP. The anomalies in resistivity at about TA = 270 K and TB = 330 K indicate that two phase transitions occur. The line shape of alp NMR spectra in different temperature ranges is attributed to the charge density distribution. The Knight shift and spin-lattice relaxation rate 1/T1T are measured from 1OK to 30OK. At about TA = 270K, they both decrease abruptly with the temperature reduction, which reveals the gap-opening behavior. Well below TA, they act like the case of normal metal. Charge-density-wave phase transition is proposed to interpret the transition occurring at about TA.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60478033, 10274017 and 10354001）, the Natural Science Foundation of Hebei Province of China （Grant No 603138）, Science and Technology Program of Hebei Province of China （Grant No 05215102）, and the Doctorate Foundation of Hebei Province of China （Grant No B2003119）.
文摘Spectral sensitization micromechanism of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr microcrystals with different dye concentrations is studied by using picosecond time-resolved fluorescence spectroscopy, and the dependences of electron transfer and spectral efficiency sensitization on different conditions are analysed in detail, With the steady spectroscopy, the wavelengths of absorption and fluorescence of J-aggregate adsorbed on AgBr microcrystals are found to shift to red relative to dye monomer. The spectrum of fluorescence has a red shift relative to the absorption peak. With the time-resolved fluorescence spectroscopy, the fluorescence decay curves of cyanine dyes J-aggregate adsorbed on the tabular and cubic AgBr grains are found to be fitted well by a double-exponential decay function. The fitting curves consist of a fast and a slow component. Because of the large amplitude of the fast component, this fast decay should be attributable mainly to the electron transfer from J-aggregate of dye to a conduction band of AgBr.
基金Supported by the National Basic Research Program of China under Grant No 2011CB921701the National Natural Science Foundation of China under Grant No 11015422the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No KJCX2-EW-W11.
文摘^(75)As nuclear magnetic resonance(NMR)was measured for Ba(Fe_(1-x)Ni_(x))_(2)As_(2)single crystals with x=0.05 and x=0.1 under 0 and 1.5GPa,respectively.For the optimal doped sample with x=0.05,the superconducting transition temperature,Tc,is strongly suppressed from 18 to 5 K,while for the over-doped sample with x=0.1,it is turned from a superconducting ground state to a disordered paramagnetic state under 1.5 GPa.Our experimental results show that the antiferromagnetic spin fluctuations,as well as Tc,are suppressed.The experimental results can be explained with the two-band model.As a result,the electronic band is shifted downwards with an increase in pressure,and the electrons become the dominant carriers in the system.
