Pairing resonance as a normal-state spin probe in ultrathin Al films

G. Catelani, Rutgers University–New Brunswick
Y. M. Xiong, Louisiana State University
X. S. Wu, Louisiana State University
P. W. Adams, Louisiana State University


We present a quantitative analysis of the low-temperature, high parallel-field pairing resonance in ultrathin superconducting Al films with dimensionless conductance g □1. In this regime we derive an analytical expression for the tunneling density-of-states spectrum from which a variety of normal-state spin parameters can be extracted. We show that by fitting tunneling data at several supercritical parallel magnetic fields we can determine all of the relevant parameters that have traditionally been obtained via fits to tunneling data in the superconducting phase. These include the spin-orbit scattering rate, the antisymmetric Landau parameter G0, and the orbital pair-breaking parameter. © 2009 The American Physical Society.