Point-Contact Spectroscopy

Point-contact Spectroscopy of Superconductors

Point-contact Spectroscopy of Magnesium Diboride with Different Counter-electrodes

We report on tunneling and Andreev-reflection conductance spectra of 39 K superconducting magnesium diboride, obtained with Pb and Au counter-electrodes. Two distinct steps at close to 2.7 and 7.1 meV appear in a low-resistance metallic-type Au-MgB2 junction characteristic, whereas a tunneling-like spectrum measured for the same junction, annealed by the application of dc current, exhibits only...

Point-contact Spectroscopy of the Nickel Borocarbide Superconductors

An overview of the recent efforts in point-contact (PC) spectroscopy of the nickel borocarbide superconductors RNi2B2C in the normal and superconducting (SC) state is given. The results of measurements of the PC electronboson(phonon) interaction spectral function are presented. Phonon maxima and crystalline-electric-field (CEF) excitations are observed in the PC spectra of compounds with R=Dy, ...

Point-contact Spectroscopy on Rusr 2 Gdcu 2 O 8

We present Point-Contact experiments on polycrystalline RuSr2GdCu2O8 samples. The majority of tunneling curves shows a zero-bias conductance peak, which is modeled by assuming a d-wave pairing symmetry of the superconducting order parameter. The magnetic field dependence of the conductance spectra has been measured in very stable junctions. In some cases, due to the granularity of the samples, ...

Theory of point contact spectroscopy in correlated materials.

We developed a microscopic theory for the point-contact conductance between a metallic electrode and a strongly correlated material using the nonequilibrium Schwinger-Kadanoff-Baym-Keldysh formalism. We explicitly show that, in the classical limit, contact size shorter than the scattering length of the system, the microscopic model can be reduced to an effective model with transfer matrix eleme...