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Tight binding models for high temperature superconductors
This page lists a set of tightbinding models that are suitable to describe high temperature superconductors
Some of the models have been compiled from the literature for comparison, others are calculated using first principles calculations or adjusted to match experimental measured quantities.
For each model, the hopping parameters are given in a comma separated file (csv), and basic plots of the band structure and Fermi surface are provided for comparison.
The tightbinding file contains lines with the following format:
r_{x}, r_{y}, r_{z}, a, b, Re(t), Im(t)
Here r_{i} is the ith component of the real space vector that describes the hopping process, a and b are integer numbers labeling the orbitals and the last two entries are the real and imaginary part of the hopping (usually given in eV).
The corresponding Bloch Hamiltonian (in orbital representation) can be obtained by a Fourier transform and summation over all lines to yield the matrix H_{ab}.

Models
10 band model for FeSe matching the eigenenergies as measured within BQPI (Sprau et al.) and consistent with ARPES measurements (Watson et al.) of the Fermi surface, and consistent with measurements of estimated areas of Fermi surface cuts via quantum oscillations (Terashima et al.).
The spin orbit coupling in this model is not encoded in the tight binding file, but included via the standart matrix elements as described in
Andreas Kreisel, Yan Wang, Thomas A. Maier, Peter J. Hirschfeld, Douglas J. Scalapino
Phys. Rev. B 88, 094522 (2013)
Spin fluctuations and superconductivity in K_{x}Fe_{2y}Se_{2}
If you use the data provided here, please cite the original work that published the tight binding parameters:

Peter O. Sprau, Andrey Kostin, Andreas Kreisel, Anna E. Böhmer, Valentin Taufour, Paul C. Canfield, Shantanu Mukherjee, Peter J. Hirschfeld, Brian M. Andersen, J.C. Séamus Davis
Science,
357, 75 (2017)
Discovery of OrbitalSelective Cooper Pairing in FeSe
A. Kreisel, Brian M. Andersen, Peter O. Sprau, Andrey Kostin, J.C. Séamus Davis, P. J. Hirschfeld
Phys. Rev. B
95, 174504 (2017)
Orbital selective pairing and gap structures of ironbased superconductors
Plot of the eigenenergies of the tightbinding parametrization along high symmetry directions of the Brillouin zone. The fat band scheme displays the weight of the dominating orbital in the wavefunction (thickness) and visualizes the character of the wavefunction (color).
The color scheme is: blue d_{xy}, red d_{xz}, green d_{yz}, black other orbitals.

Fermi surface of the 10 band model including spinorbit coupling (only the zcomponent).

Inverse Fermi velocity calculated from the tight binding model.
