Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Intrinsic Tendency of Electronic Phase Separation into Two
  Superconducting States in La(2-x)Sr(x)CuO(4+delta)   The effect of hydrostatic pressure up to 2 GPa on the superconductiong
transitions in La{2-x}Sr{x}CuO{4+delta} is investigated. The ambient and high
pressure properties of two series of samples with x=0 and x=0.015 and
0<delta<0.1 are characterized and compared by ac-susceptibility measurements.
At ambient pressure both sets of samples fit into the same phase diagram as a
function of the total hole concentration, n_h. For n_h<0.085 there is a single
superconducting transition (T_{c} approx 30 K) with an unusually large pressure
coefficient, dT_c{30}/dp approx 10K/GPa. At higher hole density (n_h>0.085) a
second superconducting transition (T_{c} approx 15 K) follows the first
transition upon cooling and the pressure shift of this transition is negative,
dT_c{15}/dp approx -4 K/GPa. At the boundary as the hole density is close to
0.085 the phase separation can be induced by pressure. The results are
explained in terms of a strong correlation of the interstitial oxygen with the
hole system in the CuO-planes. Pressure, applied at ambient temperature, causes
a redistribution of holes. The mobile oxygen dopants follow and enhance T_c as
well as the tendency to phase separation. If pressure is changed at low
temperature (<100 K) the effects on T_c and phase separations are greatly
diminished because the interstitial oxygen becomes immobile at low T. Our
results indicate that the dopant effects are important. Dopants and holes
should be treated as a single globally correlated state. When thermodynamic
euqilibrium is achieved in the soft-doping samples, we find that there is an
intrinsic tendency of electronic phase separation of doped holes into two
distinct superconducting states.

3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga