LCAO model for 3D Fermi surface of high-Tc cuprate Tl2Ba2CuO6+δ

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 x 2 −y 2 , O 2px and O 2py 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 tss between Cu 4s orbitals from neighbouring CuO2 layers. The acceptable correspondence with the experimental data gives a hint that the tss 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.

A 3D Tight‐Binding Model for La‐Based Cuprate Superconductors

“…4). We may note that band structures calculated for bilayers Bi-2212 [47,75], Tl-2201 [45], tri-layer Tl-2223 and four-layer Tl-2234 [76] revealed that the dominant interlayer hopping exhibits a γ 2 -modulation, too. In addition, Chakravarty et al [77] assumed the same γ 2 -modulation However, this perturbative treatment yields a tightbinding model different from the one of Ref.…”

“…This model has also been used in order to fit the experimental out-of-plane Fermi surface of overdoped LSCO (δ = 0.22) obtained with ARPES [41]. In addition, a three-dimensional (3D) fourband tight-binding model was derived by Mishonov et al [45] in order to explain the observation of the 3D Fermi surface in Tl 2 Ba 2 CuO 6+δ [60].…”

“…In this context, we neglect all Cu:3d orbitals but the 3d x 2 −y 2 one, so that the underlying effective low-energy model still consists of a one-band Hubbard model, but because of the BCT structure, we retain the six relevant O:2p orbitals that shape the conduction band. The often advocated Cu:4s orbital is incorporated in our model, too [35,[43][44][45][46].…”

Predicted electric field induced surface magnetization of vortex phase of superconductors

“…We believe, however, that Bi 2 Sr 2 CaCu 2 O 8 , which is easily cleaved by adhesive tape surfaces, will catalyze the development of Cooper pair mass spectroscopy. Here we have to point out that the electron band structure of over-doped high-T c cuprates is easily fitted by Linear Combination of Atomic Orbital (LCAO) method [10][11][12]. The discrepancy between the corresponding integral for optical mass that can be easily calculated and the experimentally determined Cooper pair mass will reveal how good we understand the effects of strong correlations.…”

“…Here we have to point out that the electron band structure of over-doped high-T c cuprates is easily fitted by Linear Combination of Atomic Orbital (LCAO) method. [5][6][7] The discrepancy between the corresponding integral for optical mass that can be easily calculated and the experimentally determined Cooper pair mass will reveal how good we understand the effects of strong correlations. We suppose for the pnictide superconductors the situation is the same.…”