# name
Ab initio periodic approach to electronic structure and magnetic exchange in A2CUO2X2 (A=Ca,Sr and X=F,Cl) High-Tc superconductor parent compounds

# metadata.dc.description.abstract[].value
The electronic structure of A2CuO2X2 (A5Ca, Sr and X5F ,Cl) compounds is investigated by means of the
periodic unrestricted Hartree-Fock ~UHF! method using the linear combination of atomic orbitals approach
~LCAO!. The relative stability of different alternative structures is discussed. All the systems are described as
insulators with strong ionic character and well localized spin moments on the Cu atoms. The O 2p nature of
the highest occupied bands is clear, supporting the charge transfer nature of this kind of narrow band systems;
optical gaps are however, overestimated. The magnetic ordering of these materials is two dimensional in nature
with almost independent antiferromagnetic CuO2 planes with Jc /J1;1023. The in–plane nearest (J1) and
next-nearest (J2) magnetic coupling constants are antiferromagnetic and much larger than the interplane
interactions (Jc), with J2 /J1;0.02. The relative values of the magnetic constants are in qualitative agreement
with available experimental results. None of the analyzed properties provide differences between the various
compounds so relevant to limit the possible development of a superconducting phase. On the contrary, the
close similarity between them suggest that kinetic limitations in the doping process can be responsible of the
fact that no superconducting transition has been observed in Sr2CuO2Cl2 and in the T8 phase of Sr2CuO2F2
and Ca2CuO2F2.

# metadata.dc.relation.isformatof[].value
Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.67.134513

# metadata.dc.source[].value
Articles publicats en revistes (Ciència dels Materials i Química Física)

# metadata.dc.title[].value
Ab initio periodic approach to electronic structure and magnetic exchange in A2CUO2X2 (A=Ca,Sr and X=F,Cl) High-Tc superconductor parent compounds