Zeeman splitting of the coulomb anomaly: A tunneling study in two dimensions

Wenhao Wu, Louisiana State University
J. Williams, Louisiana State University
P. Adams, Louisiana State University


We report measurements of the tunneling density of states (DOS) of ultrathin Al films in which superconductivity is quenched by a parallel magnetic field, [Formula presented]. The normal state DOS not only displays the usual logarithmic zero bias anomaly (ZBA) but also a new anomaly, superimposed on the ZBA, that appears at bias voltages [Formula presented], the electron Zeeman splitting. Measurements in tilted fields reveal that the Zeeman feature collapses with increasing perpendicular field component, suggesting that it is associated with the Cooper electron-electron interaction channel. © 1996 The American Physical Society.