Optical Conductivity of Ortho-II YBa$_2$Cu$_3$O$_6.5$

E. Bascones; T. M. Rice; A. O. Shorikov; V. I. Anisimov

doi:10.1103/physrevb.71.012505

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Optical Conductivity of Ortho-II YBa$_2$Cu$_3$O$_6.5$

E. Bascones·T. M. Rice·A. O. Shorikov·V. I. Anisimov

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Abstract

The Ortho-II phase of YBa$_2$Cu$_3$O$_6.5$ is characterized by a periodic alternation of empty Cu and filled Cu-O b-axis doubling the unit cell in the a direction. The extra oxygen in the full chains gives rise to an attractive potential for the holes in the planes. The planar bands split in two with a gap opening at the new Brillouin zone boundary $k_x=\pm pi/2$, which we estimate from LDA calculations. Using a planar model which treats the d-wave superconductivity in a mean field approximation, we show that interband transitions produce a strongly anisotropic feature in the optical conductivity controlled by a region in k-space close to ($π/2,π/2$). The edge position of this feature gives information on the temperature dependence of quasiparticle spectrum in this region. Bilayer splitting would show up as a double edge shape.

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E. Bascones, T. M. Rice, A. O. Shorikov, V. I. Anisimov. 2004-06-17. Optical Conductivity of Ortho-II YBa$_2$Cu$_3$O$_6.5$. https://doi.org/10.1103/physrevb.71.012505

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