We synthesize a set of Pd-doped polycrystalline samples PdxNdSeTe2 and measure their physical properties. Compared with pure NdSeTe2, the charge density wave （CDW） order is continuously suppressed with the Pdinterca...We synthesize a set of Pd-doped polycrystalline samples PdxNdSeTe2 and measure their physical properties. Compared with pure NdSeTe2, the charge density wave （CDW） order is continuously suppressed with the Pdintercalation. Bulk superconductivity first appears at x = 0.06 with Tc nearly 2.5I〈, coexisting with a CDW transition at 176K. Further Pd-doping enhances Tc, until it reaches the maximum value 2.84K at x=0.1, meanwhile the CDW transition vanishes. The upper critical field for the optimal doping sample Pdo.lNdSeTe2 is determined from the R-H measurement, which is estimated to be 0.6 T. These results provide another kind of ideal compound for studying the interplay between CDW and superconductivity systematically.展开更多
Photoluminescence (PL) spectra measurements have been carried out in the ternary chalcopyrite semiconductor compounds ZnGa2Se42Se4: Eu2+ using single-wavelength excitation of a Hg lamp with λ = 365 and 375 nm. Measur...Photoluminescence (PL) spectra measurements have been carried out in the ternary chalcopyrite semiconductor compounds ZnGa2Se42Se4: Eu2+ using single-wavelength excitation of a Hg lamp with λ = 365 and 375 nm. Measurements were performed at the temperature range of (120 ~ 220 K) and (110 ~ 230 K) for ZnGa2Se4 and ZnGa2Se4:Eu2+, respectively. No PL was observed for both crystals at the temperatures higher than 220 K (ZnGa2Se4) and 230 K (ZnGa2Se4:Eu2+). At temperatures lower than ~220 K and ~230 K one and three lines were observed for ZnGa2Se4 and ZnGa2Se4: Eu at 591 nm and 566, 591, 646 nm, respectively. 566 nm line was assigned as due of the 4f65d→ 4f7 (8S7/2) transition of Eu2+ ions, whereas the rest two lines were attributed to the donor-acceptor recombination pairs. Probability of non-radiation transfers (A = 108 ~109 s-1), energy of optical phonons (hω= 25 ~ 30 meV), Huan Rice parameter (S = 8 ~ 10), energy of thermal quenching (△E = 0.02 ~ 0.06 eV) were determined from the tem-perature dependences of the full width at half maximum (FWHM = Г(T)).展开更多
基金Supported by the National Basic Research Program of China under Grant No 2015CB921303the Strategic Priority Research Program(B) of the Chinese Academy of Sciences under Grant No XDB07020100
文摘We synthesize a set of Pd-doped polycrystalline samples PdxNdSeTe2 and measure their physical properties. Compared with pure NdSeTe2, the charge density wave （CDW） order is continuously suppressed with the Pdintercalation. Bulk superconductivity first appears at x = 0.06 with Tc nearly 2.5I〈, coexisting with a CDW transition at 176K. Further Pd-doping enhances Tc, until it reaches the maximum value 2.84K at x=0.1, meanwhile the CDW transition vanishes. The upper critical field for the optimal doping sample Pdo.lNdSeTe2 is determined from the R-H measurement, which is estimated to be 0.6 T. These results provide another kind of ideal compound for studying the interplay between CDW and superconductivity systematically.
文摘Photoluminescence (PL) spectra measurements have been carried out in the ternary chalcopyrite semiconductor compounds ZnGa2Se42Se4: Eu2+ using single-wavelength excitation of a Hg lamp with λ = 365 and 375 nm. Measurements were performed at the temperature range of (120 ~ 220 K) and (110 ~ 230 K) for ZnGa2Se4 and ZnGa2Se4:Eu2+, respectively. No PL was observed for both crystals at the temperatures higher than 220 K (ZnGa2Se4) and 230 K (ZnGa2Se4:Eu2+). At temperatures lower than ~220 K and ~230 K one and three lines were observed for ZnGa2Se4 and ZnGa2Se4: Eu at 591 nm and 566, 591, 646 nm, respectively. 566 nm line was assigned as due of the 4f65d→ 4f7 (8S7/2) transition of Eu2+ ions, whereas the rest two lines were attributed to the donor-acceptor recombination pairs. Probability of non-radiation transfers (A = 108 ~109 s-1), energy of optical phonons (hω= 25 ~ 30 meV), Huan Rice parameter (S = 8 ~ 10), energy of thermal quenching (△E = 0.02 ~ 0.06 eV) were determined from the tem-perature dependences of the full width at half maximum (FWHM = Г(T)).
