Eur. Phys. J. B 73, 109-115 (2010)
https://doi.org/10.1140/epjb/e2009-00407-9

LCAO model for 3D Fermi surface of high-T_c cuprate Tl₂Ba₂CuO_6+δ

Department of Theoretical Physics, Faculty of Physics, University of Sofia St. Clement of Ohrid, 5 J. Bourchier blvd., BG-1164 Sofia, Bulgaria

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Received: 15 September 2009
Published online: 1 December 2009

Abstract

A simple analytical formula for three-dimensional Fermi surface (3D FS) of Tl₂Ba₂CuO_6+δ is derived in the framework of LCAO approximation spanned over Cu 4s, Cu 3d_x²-y² , O 2p_x and O  2p_y states. This analytical result can be used for fitting of experimental data for 3D FS such as polar angle magnetoresistance oscillation. The model takes into account effective copper-copper hopping amplitude t_ss between Cu 4s orbitals from neighbouring CuO² layers. The acceptable correspondence with the experimental data gives a hint that the t_ss amplitude dominates in formation of coherent 3D FS, and other oxygen-oxygen and copper-oxygen amplitudes are rather negligible. For absolute determination of the hopping parameters a simple electronic experiment with a field effect transistor type microstructure is suggested. The thin superconductor layer is the source-drain channel of the layered structure where an AC current is applied.