Search results for "Organic superconductor"
showing 5 items of 5 documents
Disorder-induced gap in the normal density of states of the organic superconductorκ-(BEDT-TTF)2Cu[N(CN)2]Br
2015
The local density of states (DOS) of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br, measured by scanning tunneling spectroscopy on in situ cleaved surfaces, reveals a logarithmic suppression near the Fermi edge persisting above the critical temperature T(c). The experimentally observed suppression of the DOS is in excellent agreement with a soft Hubbard gap as predicted by the Anderson-Hubbard model for systems with disorder. The electronic disorder also explains the diminished coherence peaks of the quasi-particle DOS below T(c).
Scanning tunnelling spectroscopy study of paramagnetic superconducting β''-ET(4)[(H(3)O)Fe(C(2)O(4))(3)]·C(6)H(5)Br crystals.
2010
Scanning tunnelling spectroscopy (STS) and microscopy (STM) were performed on the paramagnetic molecular superconductor β''-ET(4)[(H(3)O)Fe(C(2)O(4))(3)]·C(6)H(5)Br. Under ambient pressure, this compound is located near the boundary separating superconducting and insulating phases of the phase diagram. In spite of a strongly reduced critical temperature T(c) (T(c) = 4.0 K at the onset, zero resistance at T(c) = 0.5 K), the low temperature STS spectra taken in the superconducting regions show strong similarities with the higher T(c) ET κ-derivatives series. We exploited different models for the density of states (DOS), with conventional and unconventional order parameters to take into accoun…
Comparison among superconducting models for β″-ET4[(H3O)Fe(C2O4)3]·C6H5Br single crystals by scanning tunnelling spectroscopy
2008
Single crystals of the novel superconductor beta ''-(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]center dot C6H5Br charge-transfer salt were studied using a scanning tunnelling microscope. The measured samples have an onset critical temperature of about 4.0 K. Features often reported on similar compounds were observed in the tunnelling spectra at 1.4 K. STS spectra are compared with several models for the superconducting density of states. Our analysis evidences inhomogeneous superconductivity and indicates that the presence of a magnetic layer into the sample plays a role in determining the superconducting spectroscopic features. (C) 2008 Elsevier Masson SAS. All rights reserved.
Static and dynamic interaction betweenπanddelectrons in organic superconductorβ″-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·C6H5Brstudied byC13NMR spectroscopy
2016
We present the results of $^{13}\mathrm{C}$ NMR experiments in an organic superconductor with localized Fe spins ${\ensuremath{\beta}}^{\ensuremath{''}}\ensuremath{-}{(\text{BEDT-}\mathrm{TTF})}_{4}[({\mathrm{H}}_{3}\mathrm{O})\mathrm{Fe}{({\mathrm{C}}_{2}{\mathrm{O}}_{4})}_{3}]\ifmmode\cdot\else\textperiodcentered\fi{}{\mathrm{C}}_{6}{\mathrm{H}}_{5}\mathrm{Br}$. We reveal the antiferromagnetic coupling between Fe $d$ spins and $\ensuremath{\pi}$ spins, which creates an exchange field antiparallel to the external field direction at the $\ensuremath{\pi}$ electrons. In addition to the static effects of Fe spins, we show from the nuclear spin-lattice relaxation rate measurement that the magn…
Evidence for eight node mixed-symmetry superconductivity in a correlated organic metal
2015
We report a combined theoretical and experimental investigation of the superconducting state in the quasi-two-dimensional organic superconductor $\kappa$-(ET)$_2$Cu[N(CN)$_2$]Br. Applying spin-fluctuation theory to a low-energy material-specific Hamiltonian derived from ab initio density functional theory we calculate the quasiparticle density of states in the superconducting state. We find a distinct three-peak structure that results from a strongly anisotropic mixed-symmetry superconducting gap with eight nodes and twofold rotational symmetry. This theoretical prediction is supported by low-temperature scanning tunneling spectroscopy on in situ cleaved single crystals of $\kappa$-(ET)$_2$…