Finite bias tunneling anomaly in paramagnetically limited Be films

P. W. Adams, Louisiana State University
V. Yu Butko, Louisiana State University


We report measurements of the finite bias anomaly in the tunneling density of states of homogeneously disordered superconducting Be films above the paramagnetic limit. To date the anomaly has only been reported in granular Al films and is believed to be a manifestation of a non-perturbative BCS fluctuation mechanism that forms a pseudo-gap near the Zeeman energy. We show that the magnetic field dependence of the anomaly energy in Be films is in good agreement with the recent theory of Aleiner and Altshuler provided the proper normal state Lande g-factor is used. © 2000 Elsevier Science B.V. All rights reserved.