Synthesis, crystal structures and luminescent properties of the copper(I) pyrazolonate complexes

© 2014 Elsevier B.V. All rights reserved. New copper(I) complexes with pyrazolonate ligands [Cu(Pri-PMP)(DPEphos)] (1) and [Cu(But-PMP)(DPEphos)] (2) (Pri-PMP = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolonato, But-PMP = 1-phenyl-3-methyl-(2,2-dimethylpropan-1-oyl)-5-pyrazolonato; DPEphos = bis[2-(diphenylphosphino)-pheny]ether) were synthesized and structurally characterized. An unusual η1 coordination of pyrazolonate ligand to the copper atom was found in complex 2. Photo- and electroluminescent properties of the synthesized compounds were investigated. In crystalline form compounds 1 and 2 revealed dual emission consisting of the bands at 445-450 and 485-488 nm which were assigned to transitions from the S1 and T1 states. DFT and TD DFT calculations as well as electrochemical studies correlate with the photophysical data. Synthesized copper(I) complexes generated electroluminescence of yellowish-orange (1) and yellow (2) colors with the maximum luminance of 286 and 39 cd/m2, respectively

Josephson effect in d-wave superconductor junctions in a lattice model

Josephson current between two d-wave superconductors is calculated by using a lattice model. Here we consider two types of junctions, $i.e.$, the parallel junction and the mirror-type junction. The maximum Josephson current $(J_{c})$ shows a wide variety of temperature ($T$) dependence depending on the misorientation angles and the types of junctions. When the misorientation angles are not zero, the Josephson current shows the low-temperature anomaly because of a zero energy state (ZES) at the interfaces. In the case of mirror-type junctions, $J_c$ has a non monotonic temperature dependence. These results are consistent with the previous results based on the quasiclassical theory. [Y. Tanaka and S. Kashiwaya: Phys. Rev. B \textbf{56} (1997) 892.] On the other hand, we find that the ZES disappears in several junctions because of the Freidel oscillations of the wave function, which is peculiar to the lattice model. In such junctions, the temperature dependence of $J_{c}$ is close to the Ambegaokar-Baratoff relation.Comment: 17 pages, 10 figures, using jpsj2.cls and oversite.st

Theory of charge transport in diffusive normal metal / conventional superconductor point contacts

Tunneling conductance in diffusive normal metal / insulator / s-wave superconductor (DN/I/S) junctions is calculated for various situations by changing the magnitudes of the resistance and Thouless energy in DN and the transparency of the insulating barrier. The generalized boundary condition introduced by Yu. Nazarov [Superlattices and Microstructures 25 1221 (1999)] is applied, where the ballistic theory by Blonder Tinkham and Klapwijk (BTK) and the diffusive theory by Volkov Zaitsev and Klapwijk based on the boundary condition of Kupriyanov and Lukichev (KL) are naturally reproduced. It is shown that the proximity effect can enhance (reduce) the tunneling conductance for junctions with a low (high) transparency. A wide variety of dependencies of tunneling conductance on voltage bias is demonstrated including a $U$-shaped gap like structure, a zero bias conductance peak (ZBCP) and a zero bias conductance dip (ZBCD)