https://doi.org/10.1140/epjb/e2002-00210-2
Zero bias anomaly in the density of states of low-dimensional metals
Institut für Theoretische Physik, Universität Frankfurt, Robert-Mayer-Str. 8-10, 60054 Frankfurt am Main, Germany
Corresponding author: a bartosch@itp.uni-frankfurt.de
Received:
28
August
2001
Revised:
28
January
2002
Published online:
9
July
2002
We consider the effect of Coulomb interactions
on the average density of states (DOS)
of disordered low-dimensional metals
for temperatures T and frequencies ω smaller than the
inverse elastic life-time 
.
Using the fact that long-range Coulomb interactions
in two dimensions (2d) generate
in the DOS
but only 
-singularities in the conductivity
, we can re-sum the most singular contributions to the
average DOS via a simple gauge-transformation.
If 
,
then a metallic Coulomb gap
appears in the DOS at T=0 for frequencies below a certain crossover
frequency 
which depends on the
value of the DC conductivity 
.
Here, 
is the charge of the electron.
Naively adopting the same procedure to calculate the DOS in quasi 1d
metals, we find 
at ,
where 
is some interaction-dependent
frequency scale. However, we argue that in quasi 1d
the above gauge-transformation method is on less firm grounds
than in 2d.
We also discuss the behavior of
the DOS at finite temperatures and give numerical results for the
expected tunneling conductance that can be compared with
experiments.
PACS: 71.10.Pm – Fermions in reduced dimensions / 71.23.-k – Electronic structure of disordered solids / 71.30.+h – Metal-insulator transitions and other electronic transitions / 72.15.Rn – Localization effects (Anderson or weak localization)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002
