This is what a typical
kite.Configuration object (for a 2D lattice) looks like:
divisionsis an integer number that defines the number of decomposition parts in each spatial direction. KITEx implements a domain decomposition technique to divide the lattice into various partitions that are computed in parallel. The domain decomposition is optimized at the design level and allows a substantial speed up of multithreaded calculations, it's usage is recommended.
- To activate this feature, set a number of decomposition parts larger than one
nx * ny * nz > 1.
nx * ny * nzequals the number of threads used by KITEx and thus must not exceed the number of available cores in the computer.
lengthis an integer number of unit cells along the direction of lattice vectors
lx, ly, lz = 256, 256, 256. The lateral size of the decomposed parts are given by
The laterial sizes
lz/nzmust be integers.
When using a 2D lattice, only
lx, ly, nx, nyare needed.
KITE has 3 standard types of boundary conditions (BCs) implemented, namely: periodic, open, and twisted. Moreover, a "random BCs" option is available, whereby statistical averages over ensembles of random vectors (or disorder configurations) are done with the help of random twist angles drawn from a uniform distribution. This special option is particularly useful to simulate the infinite-size “bulk", since it efficiently eliminates finite size effects.
It is possible to impose open BCs along one spatial direction to build ribbons in 2D and slabs in 3D.
boundariesis a string, use
'periodic'for periodic BCs,
'open'for open BCs,
'twisted'for twisted BCs and
'random'for random BCs. In all cases, the system has the geometry of the unit cell, which is replicated
lx, ly, lztimes in the directions of the unit vectors. Different BCs can be used along the
zaxis. If twisted boundary conditions are used, the twist
anglesmust be included in radians.
For twisted BCs, the twist phase angles need to be specified by the user. This is done by means of an extra argument
' phi_i \in [0, 2*M_PI]'. The syntax is simple:
Random BCs are defined using
mode = 'random'. No extra arguments are required, but this option implicitely assumes that many random vectors (and/or disorder configurations) will be used. For a single system realization (Sec. calculation for calculation settings), this option is equivalent to a mere twisted-BC simulation with randomly chosen twist-angles along
The usage of
Falsefor the boundaries is deprecated.
is_complexis a boolean value. For optimisation purposes, KITEx only considers and stores complex data with the setting
Falseshould be used for real symmetric Hamiltonians.
precisionis an integer identifier for the used data type. KITEx allows users to define the precision of the calculation. Use
1for double, and
2for long double.
spectrum_rangeis an array of reals. By default, KITEx executes an automated rescaling of the Hamiltonian, see the Documentation. Advanced users should avoid the automated rescaling and override this feature using
Emin, Emaxare the minimum, maximum eigenvalues of the TB matrix. Lower/upper bounds on smallest/largest energy eigenvalues should be used if exact eigenvalues are unknown (often the case in systems with disorder); see Sec. Disorder for more information.