Tuesday, April 16, 2013

1304.3565 (T. Jarlborg et al.)

Effects of excess or deficiency of oxygen content on the electronic
structure of high-$T_C$ cuprates

T. Jarlborg, A. Bianconi, B. Barbiellini, R. S. Markiewicz, A. Bansil
Band structure calculations are presented for large supercells of Ba$_2$CuO$_4$ (BCO) with O-vacancies in planar or apic al positions, and of superoxygenated La$_2$CuO$_4$ (LCO) with oxygen interstitials in the La$_2$O$_2$ layers. It is foun d that apical oxygen vacancies in BCO act as electron dopants and makes the electronic structure similar to that of hole doped LCO. Excess oxygen interstitials forming wires in the La$_2$O$_2$ layers of LCO are shown to yield a much larger density-of-states at the Fermi energy than for the stoichiometric compound related with a segmentation of the Fermi surface. Anti-ferromagnetic (AFM) spin fluctuations are strengthened by O-vacancies in BCO as well as by oxygen interstitials in LCO, but are strongly suppressed in O-deficient LCO. Our results indicate the complexity of doping by O-vacancies, and by ordered defects that are a significant factor contr olling the electronic properties of cuprates.
View original: http://arxiv.org/abs/1304.3565

No comments:

Post a Comment