19 research outputs found
Differential conductance of point contacts between an iron-based superconductor and a normal metal
We present a theoretical description of the differential conductance of point
contacts between a normal metal and a multi-band superconductor with extended
s\pm pairing symmetry. We demonstrate that the interband impurity scattering
broadens the coherent peak near the superconducting gap and significantly
reduces its height even at relatively low scattering rates. This broadening is
consistent with a number of recent experiments performed for both tunnel
junctions and larger diffusive contacts. Our theory helps to better evaluate
the energy gap of iron-based superconductors from point contact Andreev
spectroscopy measurements.Comment: 5 pages, 4 figure
Magnetic penetration depth in the presence of a spin-density wave in multiband superconductors at zero temperature
We present a theoretical description of the London penetration depth of a
multi-band superconductor in the case when both superconducting and
spin-density wave orders coexist. We focus on clean systems and zero
temperature to emphasize the effect of the two competing orders. Our
calculation shows that the supefluid density closely follows the evolution of
the superconducting order parameter as doping is increased, saturating to a BCS
value in the pure superconducting state. Furthermore, we predict a strong
anisotropic in-pane penetration depth induced by the spin-density wave order.Comment: 7 pages, 4 figure
Engelen, Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. I. Spectra of protiated and partially deuterated magnesium potassium phosphate hexahydrate
Abstract The Fourier transform infrared and Raman spectra of magnesium potassium phosphate hexahydrate and a series of its deuterated analogues were recorded and analyzed. By comparing the spectra recorded at room temperature with those obtained at the boiling temperature of liquid nitrogen and by studying the spectra of the series of partially deuterated MgKPO 4 ·H 2 O an assignment was proposed for the observed bands. The unusual behavior for bands originating from the n 4 modes of PO 4 32 ions in the Raman spectra of partially deuterated analogues of MgKPO 4 ·6H 2 O was explained by coupling and mixing of the n 4 ðPO 4 Þ mode and D 2 O librations.