This page contains most of the input necessary for control of the tight-binding part of the code.

I order to call the tight-binding part of matjes, the:

simulation tight-binding

keyword has to be specified.

Control of functionalities

It is necessary to manually enable all parts of the tight-binding part functionality and especially whether the real and/or reciprocal part will be used (do_TB_r, do_Tb_k).

real-space

do_TB_r use real-space TB-module (logical, default: F)

do_spec_r print out the energy spectrum (logical, default: F)

do_dos_r calculate density of states (logical, default: F)

do_fermi_r calculate Fermi energy (logical, default: F)

do_occ_r print occupation distribution at the Fermi energy (logical, default: F)

do_occ_mult_r print occupation distribution at several energies (logical, default: F)

reciprocal-space

do_TB_k use reciprocal-space TB-module (logical, default: F)

do_dos_k calculate density of states (logical, default: F)

do_fermi_dos_k calculate Fermi energy projections (logical, default: F)

do_highs_k calculate bandstructure (logical, default: F)

do_highs_k calculate bandstructure (logical, default: F)

do_proj_energy integrates energy times projected weight for all orbitals for all occupied states (logical, default: F)

Hamiltonian setup

Hamiltonian input

A description of the necessary input for the different terms can be found here.

TB_hopping hopping parameters

TB_delta s-type delta

TB_scfdelta self-consistent s-type delta

TB_Jsd Jsd coupling

TB_Efermi modifies Fermi level (real, default 0)

wann_ham wannier Hamiltonian (string)

wann_up_ham wannier Hamiltonian for up-states only (string)

wann_dn_ham wannier Hamiltonian for down-states only (string)

IO-options

In the case of the real-space calculation it can make sense to store the eigenvalues and eigenvectors.

TB_write_solution_r write calculated diagonalization (logical, default: F)

TB_read_solution_r read previously calculated diagonalization (logical, default: T)

Diagonalization options

TB_sparse Decides if sparse or dense diagonalization routines are used (logical, default false)

TB_diag Integer choosing between diagonalization routine in the dense case (1:zheevd, 2:zheev, 3:feast, 4:zheevr) (integer,default:1)

TB_diag_acc Accuracy for diagonalization algorithms (real, default:1d-12)

TB_diag_Ebnd minimal and maximal eigenvalue energy for diagonalization where that matters (2 reals, default 0.0 0.0)

TB_diag_Emin alternative input for TB_diag_Ebnd(1) (real)

TB_diag_Emax alternative input for TB_diag_Ebnd(2) (real)

TB_diag_estNe estimation for number of eigenvalue or energy subspace size in considered energy range where that matter (integer, default:0)

Self-consistent superconductivity

TB_scf_print print intermediate delta steps (logical, default: false)

TB_scf_loopmax maximal number of self-consistenct loop (integer default: 100)

TB_scf_Ecut Energy cutoff for scf delta calculation (real default: -1.0 <- no cutoff)

TB_scf_kgrid k-grid dimension for scf-loop (3 integers, default: 10 10 1)

TB_scf_kmesh_file file name for kmesh integration grid input (string)

TB_scf_diffconv convergence criterion for self-consistent loop (real default: 1.0d-6)

Band-structure

N_highsym number of high-symmetry points (integer, default 0)

k_highs_pts position of high-symmetry k-points in units of the reciprocal lattice (3*N_highsym reals)

k_highs_frac divisor to apply to high symmetry k-point (eg. 3) (N_highsym integer, default:1)

k_highs_dist aimed distance between neighboring k-points in units of reciprocal lattice (real, default: 0.01)

Density of states

dos_E_ext energy window boundaries (2 reals, default: -1.0 1.0)

dos_dE energy resolution stepsize (real, default: 0.01)

dos_sigma gauss smearing parameter for dos (real, default: 0.01)

dos_kgrid kgrid size for dos integration (3 integers, default: 1 1 1)

dos_print_kint print index of currently calculating k-point (logical, default: F)

dos_kmesh_file alternative possibility to insert kmesh data through a file (string)

local DOS

TB_loc_dos number of site for which the local dos is plotted (integer), followed by lines with further input

orbital DOS

TB_orb_dos number of orbitals for which the orbital dos is plotted (integer), followed by lines with further input

Fermi energy distribution

N_fermi_orb Number of orbital indices of projections for fermi-surfaces (integer)

fermi_orb orbital indices of projections for fermi-surfaces

fermi_proj_all plot the Fermi distributions for all orbitals (logical, default: F)

Multiple occupation distribution

occ_mult_E_ext minimal and maximal energy considered (2 reals, default: 0.0 0.0)

occ_mult_dE energy step size (real, default: -1.0)

occ_mult_kt occupation energy smearing (real, default:-1.0)

Fermi energy

Rather obsolete input to set/calculate the Fermi energy in real-space setup

N_electrons number of electrons (reals, default: -1.0)

fermi_kt fermi energy calculation smearing (real, default: 0.001)

TB_EF input Fermi energy, rather obsolete only used for occupation distribution (do_occ_r) (real, default: 0.0)