Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic structure of the $Sr_{0.4}Ca_{13.6}Cu_{24}O_{41}$
  incommensurate compound   We extracted, from strongly-correlated ab-initio calculations, a complete
model for the chain subsystem of the $Sr_{0.4}Ca_{13.6}Cu_{24}O_{41}$
incommensurate compound. A second neighbor $t-J+V$ model has been determined as
a function of the fourth crystallographic parameter $\tau$, for both low and
room temperature crystallographic structures. The analysis of the obtained
model shows the crucial importance of the structural modulations on the
electronic structure through the on-site energies and the magnetic
interactions. The structural distortions are characterized by their long range
effect on the cited parameters that hinder the reliability of analyses such as
BVS. One of the most striking results is the existence of antiferromagnetic
nearest-neighbor interactions for metal-ligand-metal angles of $90^\circ$. A
detailed analysis of the electron localization and spin arrangement is
presented as a function of the chain to ladder hole transfer and of the
temperature. The obtained spin arrangement is in agreement with
antiferromagnetic correlations in the chain direction at low temperature.

16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph