Simple code to obtain the dispersion curve and z component of spin-spin correlation for a 1D Tight Binding model.
---------------------- 1D Tight Binding Model --------------------
Author: João Augusto Sobral da Silva / Github: @joaosds
The code is commented, and each subroutine has a brief description (B.D.) of its functionality. For any discussions you can contact me at Github!
History:
v1.0 (04/30/20) - First implementation v1.1 (08/20/20 - Comments, cleaning code, and python script for plots
Future intended changes:
- implementation of modern fortran (>=2008);
- hamiltonian matrix determination from a neighbor's lattice;
- python script for plots;
- python interface to link both the fortran file and the plots automatically;
File 'disp.dat' prints the eigenvalues ordered by increasing order and the original order from the LAPACK function DSYEV;
File 'parameters.dat' informs the initial parameters N,t, BC: number of sites, value of hopping parameter t and lattice boundary condition. Type 0 for periodic, 1 for anti-periodic and 2 for open conditions.
File 'dispanaly.dat' displays the expected eigenvalues by the analytical expression. It can be compared to the 2nd column of file 'disp.dat'.
File 'spincor.dat' informs the z component of the spin-spin correlation as obtained from the eigenfunctions of the DSEYV function;
File 'spincor.dat' shows the expected spin-spin correlation by the discrete analytical expression.
Note: For theoretical background see pdf "Tight Binding 1D implementation.pdf"