kwant.solvers.common.
GreensFunction
(data, lead_info, out_leads, in_leads, current_conserving=False)[source]¶Bases: kwant.solvers.common.BlockResult
Retarded Green’s function.
Transport properties can be easily accessed using the
transmission
method (don’t be fooled by the name, it can
also compute reflection, which is just transmission from one lead back into
the same lead).
GreensFunction
however also allows for a more direct access to the
result: The data stored in GreensFunction
is the real-space Green’s
function. The details of this data can be directly accessed through the
instance variables data and lead_info. Subblocks of data corresponding
to particular leads are conveniently obtained by
submatrix
.
Attributes
data | (NumPy array) a matrix containing all the requested matrix elements of Green’s function. |
lead_info | (list of matrices) a list with self-energies of each lead. |
out_leads, in_leads | (sequence of integers) indices of the leads where current is extracted (out) or injected (in). Only those are listed for which SMatrix contains the calculated result. |
Methods
block_coords
(lead_out, lead_in)[source]¶Return slices corresponding to the block from lead_in to lead_out.
conductance_matrix
()[source]¶Return the conductance matrix.
This is the matrix \(C\) such that \(I = CV\) where \(I\) and \(V\) are, respectively, the vectors of currents and voltages for each lead.
This matrix is useful for calculating non-local resistances. See Section 2.4 of the book by S. Datta.
in_block_coords
(lead_in)[source]¶Return a slice with the columns in the block corresponding to lead_in.
out_block_coords
(lead_out)[source]¶Return a slice with the rows in the block corresponding to lead_out.
transmission
(lead_out, lead_in)[source]¶Return transmission from lead_in to lead_out.
If the option current_conserving
has been enabled for this object,
this method will deduce missing transmission values whenever possible.
Current conservation is enabled by default for objects returned by
smatrix
and
greens_function
whenever the Hamiltonian has
been verified to be Hermitian (option check_hermiticity
, enabled by
default).