Scaling Behavior of the Longitudinal and Transverse Transport in Quasi One-Dimensional Organic Conductors
M. Dressel, K. Petukhov, B. Salameh, P. Zornoza, T. Giamarchi
Abstract
We report on dc and microwave experiments of the low-dimensional organic conductors (TMTSF)
2
PF
6
and (TMTSF)
2
ClO
4
along the
a
,
b
′
, and
c
∗
directions. In the normal state of (TMTSF)
2
PF
6
below T=70 K, the dc resistivity follows a power-law with
ρ
a
and
ρ
b
′
proportional to
T
2
while
ρ
c
∗
∝T
. Above
T=100
K the exponents extracted from the data for the
a
and
c
∗
axes are consiste1nt with what is to be expected for a system of coupled one-dimensional chains (Luttinger liquid) and a dimensional crossover at a temperature of about 100 K. The
b
′
axis shows anomalous exponents that could be attributed to a large crossover between these two regimes. The contactless microwave measurements of single crystals along the
b
′
-axis reveal an anomaly between 25 and 55 K which is not understood yet. The organic superconductor (TMTSF)
2
ClO
4
is more a two-dimensional metal with an anisotropy
ρ
a
/
ρ
b
′
of approximately 2 at all temperatures. Such a low anisotropy is unexpected in view of the transfer integrals. Slight indications to one-dimensionality are found in the temperature dependent transport only above 200 K. Even along the least conducting
c
∗
direction no region with semiconducting behavior is revealed up to room temperature.