qimpy.transport.material.FermiCircle

class FermiCircle(*, kF, vF, N_theta, tau_p, tau_ee, r_c=inf, theta0=0.0, specularity=1.0, process_grid, checkpoint_in=(None, ''))

Bases: Material

Fermi-circle representation suitable for graphene and 2DEGs.

Parameters:

kF (float)
vF (float)
N_theta (int)
tau_p (float)
tau_ee (float)
r_c (float)
theta0 (float)
specularity (float)
process_grid (ProcessGrid)
checkpoint_in (CheckpointPath)

__init__(*, kF, vF, N_theta, tau_p, tau_ee, r_c=inf, theta0=0.0, specularity=1.0, process_grid, checkpoint_in=(None, ''))

Initialize Fermi-circle model material.

Parameters:

kF (float) – [Input file] Fermi wave vector in atomic units.
vF (float) – [Input file] Fermi velocity in atomic units.
N_theta (int) – [Input file] Number of k along Fermi circle.
theta0 (float) – [Input file] Angle of first k-point.
r_c (float) – [Input file] Cyclotron radius, corresponding to external magnetic field. If infinite, disable magentic field (default).
specularity (float) – [Input file] Specularity of reflection at all surfaces. Should be in the range of 0 for fully diffuse scattering, to 1 for perfectly specular reflection.
tau_p (float)
tau_ee (float)
process_grid (ProcessGrid)
checkpoint_in (CheckpointPath)

Methods

`__init__`	Initialize Fermi-circle model material.
`accumulate_edges`	Accumulate momentum-space advection edge contributions outL and outR into out, and return out for convenience.
`add_child`	Construct child object self.`attr_name` of type cls.
`add_child_one_of`	Invoke add_child on one of several child options in args.
`get_contactor`	Return a function (or callable object) to calculate the distribution function at a contact with orientation n and specified keyword arguments.
`get_observable_names`	Return list of observable names, specific to each material.
`get_observables`	Return tensor of complex conjugates of all observables specific to each material.
`get_reflector`	Return a function (or callable object) to calculate reflections for a sequence of surface points with unit normals (Nsurf x 2).
`initialize`	Initialize shared material parameters (call from a derived class.)
`initialize_fields`	Initialize spatially-dependent / parameter sweep values.
`measure_observables`	Return expectation value of observables, (Nx x Ny x No).
`pad_ghost`	Pad by ghost zones for monetum-space advection.
`rho_dot`	Return material contribution to drho/dt.
`rho_dot_collisions`
`save_checkpoint`	Save self and all children in hierarchy to cp_path.

Attributes

`transport_velocity`	Effective velocity for each density-matrix component.
`kF`	Fermi wave-vector
`vF`	Fermi velocity
`tau_inv_p`	Momentum relaxation rate
`tau_inv_ee`	Electron internal scattering rate (momentum-conserving)
`theta0`	Initial angle in fermi circle grid
`specularity`	Specularity of reflection at all boundaries
`r_c`	Cyclotron radius for extenral magnetic field (disabled if infinity)
`F_theta`	Angular force in grid coordinates
`advect`	Momentum-space advection logic
`comm`	Communicator for reciprocal-space split over k
`k_division`	Division of k-points over MPI
`k_mine`	slice of k on current process
`nk_mine`	number of k-points on current process
`n_bands`	number of bands at each k
`n_dim`	dimensionality of material (2 or 3)
`wk`	Brillouin zone integration weight
`k`	nk_mine x n_dim wave vectors
`E`	nk_mine x n_bands energies
`v`	nk_mine x n_bands x n_dim velocities in plane
`rho0`	nk_mine x n_bands x n_bands initial density matrix
`dt_max`	maximum stable time-step (set to inf if not available)
`child_names`	Names of attributes with child objects.
`variant_name`	Version of children having variants (if any)

accumulate_edges(out, outL, outR)

Accumulate momentum-space advection edge contributions outL and outR into out, and return out for convenience.

Parameters:

out (Tensor)
outL (Tensor)
outR (Tensor)

Return type:

Tensor

get_contactor(n, **kwargs)

Return a function (or callable object) to calculate the distribution function at a contact with orientation n and specified keyword arguments. For an Nsurf x 2 tensor n, the function should take time t as an input and return the corresponding Nsurf x Nkbb_mine distribution function.

Parameters:: n (Tensor)
Return type:: Callable[[float], Tensor]

get_observable_names()

Return list of observable names, specific to each material.

Return type:: list[str]

get_observables(t)

Return tensor of complex conjugates of all observables specific to each material. (No x Nkbb_mine) where No is number of observables.

Parameters:: t (float)
Return type:: Tensor

get_reflector(n)

Return a function (or callable object) to calculate reflections for a sequence of surface points with unit normals (Nsurf x 2). This function will be called with a Nghost x Nsurf x Nkbb_mine tensor, and the reflection should be calculated pointwise in real-space with output of the same dimensions.

Parameters:: n (Tensor)
Return type:: Callable[[Tensor], Tensor]

initialize_fields(rho, params, patch_id)

Initialize spatially-dependent / parameter sweep values. Using named properties params, containing tensors that should broadcast with the grid dimensions, update the density matrix rho to be spatially varying if necessary and calculate any named fields for use during dynamics. Note that the cached quantities must be associated with patch_id, as there may be multiple spatial domains (patches) sharing the same material.

Parameters:

rho (Tensor)
params (dict[str, Tensor])
patch_id (int)

Return type:

None

pad_ghost(rho)

Pad by ghost zones for monetum-space advection.

Parameters:: rho (Tensor)
Return type:: Tensor

rho_dot(rho, t, patch_id)

Return material contribution to drho/dt. This should include scattering and any coherent evolution in band space.

Parameters:

rho (Tensor)
t (float)
patch_id (int)

Return type:

Tensor

F_theta: float: Angular force in grid coordinates

advect: ScriptModule: Momentum-space advection logic

kF: float: Fermi wave-vector

r_c: float: Cyclotron radius for extenral magnetic field (disabled if infinity)

specularity: float: Specularity of reflection at all boundaries

tau_inv_ee: float: Electron internal scattering rate (momentum-conserving)

tau_inv_p: float: Momentum relaxation rate

theta0: float: Initial angle in fermi circle grid

vF: float: Fermi velocity