Influence of the incommensurability in $Sr_{14-x}Ca_xCu_{24}O_{41}$ family compounds

摘要

The present paper studies the influence of the structural modulation on thelow energy physics of the $Sr_{14-x}Ca_xCu_{24}O_{41}$ oxides, using ab-initiodetermination of the on-site and nearest neighbor effective parameters. Thestructural modulations appears to be the key degree of freedom, responsible forthe low energy properties, such as the electron localization, the formation ofdimers in the $x=0$ compound or the anti-ferromagnetic order in the $x=13.6$compound.