Trans file

This file determines the coefficients of the transfer integrals $t_{ij{\sigma }_1{\sigma }_2}$ in the Hamiltonian

(3.3)$$\begin{array}{r}\mathcal{H}=-\sum _{ij{\sigma }_1{\sigma }_2}{t}_{ij{\sigma }_1{\sigma }_2}{c}_{i{\sigma }_1}^{†}{c}_{j{\sigma }_2}^{\phantom{†}}.\end{array}$$

An example of the file format is presented below.

========================
NTransfer      24
========================
========i_j_s_tijs======
========================
    0     0     2     0   1.000000  0.000000
    2     0     0     0   1.000000  0.000000
    0     1     2     1   1.000000  0.000000
    2     1     0     1   1.000000  0.000000
    2     0     4     0   1.000000  0.000000
    4     0     2     0   1.000000  0.000000
    2     1     4     1   1.000000  0.000000
    4     1     2     1   1.000000  0.000000
    4     0     6     0   1.000000  0.000000
    6     0     4     0   1.000000  0.000000
    4     1     6     1   1.000000  0.000000
    6     1     4     1   1.000000  0.000000
    6     0     8     0   1.000000  0.000000
    8     0     6     0   1.000000  0.000000
…

File format

• Line 1: Header

• Line 2: [ntransfer] [count]

• Lines 3-5: Header

• Lines 6-: [i] [s1] [j] [s2]  [v.real] [v.imag]

Parameters

• [ntransfer]

  Type : String (blank is not allowed)

  Description : An arbitrary keyword for the total number of transfer integrals.

• [count]

  Type : Integer (blank is not allowed)

  Description : An integer giving the total number of transfer integrals.

• [i], [j]

  Type : Integer (blank is not allowed)

  Description : An integer giving a site index ($0\le i,j<\mathrm{N}\mathrm{s}\mathrm{i}\mathrm{t}\mathrm{e}$).

• [s1], [s2]

  Type : Integer (blank is not allowed)

  Description : An integer giving a spin index: either 0 (up-spin) or 1 (down-spin).

• [v.real], [v.imag]

  Type : Float (blank is not allowed)

  Description : Values for the real and imaginary parts of $t_{ij{\sigma }_1{\sigma }_2}$, respectively.

Usage rules

• Headers cannot be omitted.

• Since the Hamiltonian should be hermite, the coefficients must satisfy the relation $t_{ij{\sigma }_1{\sigma }_2}=t_{ji{\sigma }_2{\sigma }_1}^{†}$. Otherwise, the program is terminated or a warning is reported, depending on the strict_hermite parameter.

• The program is terminated with error if there are duplicated entries.

• The program is terminated with error when the number of entries is different from [count].

• The program is terminated with error if [i], [j], [s1], or [s2] are outside the range of the defined values.