Vy. Butko et al., Exchange fields and the finite bias tunneling anomaly in paramagnetically limited superconducting Al films, PHYS REV L, 82(21), 1999, pp. 4284-4287
We present an experimental investigation of the finite bias anomaly in the
tunneling density of states of superconducting Al films above the paramagne
tic limit. We show that the anomaly is a manifestation of a new fluctuation
mechanism that forms a pseudogap near the Zeeman energy. The field depende
nce of the anomaly energy is in good agreement with the recent theory of Al
einer and Altshuler, provided that the proper normal-state Lande a factor i
s used. We argue that the normal-state g factor is reduced from the bare va
lue of g(n) = 2 to g(n) - 1.7 by a negative exchange field in the paramagne
tic phase. [S0031-9007199)09200-5].