Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor

In the presence of an external magnetic field, the low lying elementary excitations of a d-wave superconductor have quantized energy and their momenta are locked near the node direction. It is argued that these discrete states can most likely be detected by a local probe, such as a scanning tunneling microscope. The low temperature local tunneling conductance on the Wigner-Seitz cell boundaries of the vortex lattice is predicted to show peaks spaced as $\pm \sqrt{n}, n ={0,1,2, ...}$. The $n=0$ peak is anomalous, and it is present only if the superconducting order parameter changes sign at certain points on the Fermi surface. Away from the cell boundary, where the superfluid velocity is nonzero, each peak splits, in general, into four peaks, corresponding to the number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included

New wavelength measurements and laser lines in optically pumped methanol and methanol analogues

We present accurate measurements of 8 frequently used CW far infrared laser lines which we found substantially in error in the litterature. We also present measurements of 8 newly observed lines

New wavelength measurements and laser lines in optically pumped methanol and methanol analogues

We present accurate measurements of 8 frequently used CW far infrared laser lines which we found substantially in error in the litterature. We also present measurements of 8 newly observed lines.Nous présentons des mesures précises des longueurs d'onde de 8 raies fréquemment utilisées en spectroscopie laser dans l'infrarouge lointain, leurs longueurs d'onde citées dans la littérature étant erronées. Nous présentons également les mesures de 8 nouvelles raies que nous avons observées

Optical excitation of quasiparticle pairs in the vortex core of high-Tc superconductors

A far-infrared resonance has been observed in superconducting YBa2Cu3O7 thin films in the presence of high magnetic fields. It corresponds to the quasiparticle pair creation process inside the vortex core. The resonance frequency is ω0=1.3kTc/Latin small letter h with stroke with a linewidth 1/τ0.6ω. This value for ω0 implies, within BCS theory, a large energy gap in YBa2Cu3O7. © 1992 The American Physical Society.link_to_subscribed_fulltex