759 research outputs found
Crystal Symmetry, Electron-Phonon Coupling, and Superconducting Tendencies in LiPdB and LiPtB
After theoretical determination of the internal structural coordinates in
LiPdB, we calculate and analyze its electronic structure and obtain the
frequencies of the two phonons (40.6 meV for nearly pure Li mode, 13.0
meV for the strongly mixed Pd-Li mode). Pd can be ascribed a
configuration, but strong 4d character remains up to the Fermi level. Small
regions of flat bands occur at -70 meV at both the and X points.
Comparison of the Fermi level density of states to the linear specific heat
coefficient gives a dynamic mass enhancement of = 0.75. Rough Fermi
surface averages of the deformation potentials of individual Pd and Li
displacements are obtained. While is small, ~ 1.15 eV/\AA
is sizable, and a plausible case exists for its superconductivity at 8 K being
driven primarily by coupling to Pd vibrations. The larger d bandwidth in
LiPtB leads to important differences in the bands near the Fermi
surface. The effect on the band structure of spin-orbit coupling plus lack of
inversion is striking, and is much larger in the Pt compound.Comment: 8 pages and 8embedded figures, to be appeared in PR
Charge-transfer induced surface conductivity for a copper based inorganic-organic hybrid
Inorganic-organic hybrids are receiving increasing attention as they offer the opportunity to combine the robust properties of inorganic materials with the versatility of organic compounds. We have studied the electric properties of an inorganic-organic hybrid with the chemical formula: CuCl4(C6H5CH2CH2NH3)2. This material is a ferromagnetic insulator that can easily be processed from solution. We show that the surface conductivity of the hybrid can be increased by five orders of magnitude by covering the surface with an organic electron donor. This constitutes a novel method to dope perovskite-based materials and study their charge transport properties.
Effect of Pt doping on the critical temperature and upper critical field in YNi2-xPtxB2C (x=0-0.2)
We investigate the evolution of superconducting properties by doping
non-magnetic impurity in single crystals of YNi2-xPtxB2C (x=0-0.2). With
increasing Pt doping the critical temperature (Tc) monotonically decreases from
15.85K and saturates to a value ~13K for x>0.14. However, unlike conventional
s-wave superconductors, the upper critical field (HC2) along both
crystallographic directions a and c decreases with increasing Pt doping.
Specific heat measurements show that the density of states (N(EF)) at the Fermi
level (EF) and the Debye temperatures (Theta_D) in this series remains constant
within the error bars of our measurement. We explain our results based on the
increase in intraband scattering in the multiband superconductor YNi2B2C.Comment: ps file with figure
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