def get_imag_self_energy(interaction,
grid_points,
sigmas,
frequency_step=None,
num_frequency_points=None,
temperatures=None,
scattering_event_class=None, # class 1 or 2
run_with_g=True,
write_details=False,
log_level=0):
"""Imaginary part of self energy at frequency points
Band indices to be calculated at are kept in Interaction instance.
Args:
interaction: Ph-ph interaction
grid_points: Grid-point indices to be caclculated on
sigmas:
A set of sigmas. simga=None means to use tetrahedron method,
otherwise smearing method with real positive value of sigma.
frequency_step: Pitch of frequency to be sampled.
num_frequency_points: Number of sampling sampling points to be used
instead of frequency_step.
temperatures: Temperatures to be calculated at.
scattering_event_class:
Extract scattering event class 1 or 2. This can be enabled only when
run_with_g is True.
run_with_g:
Integration weigths are calculated from gaussian smearing function.
More memory space is required, but a consistent routine can be used
both in tetrahedron method and smearing method.
log_level: Log level. 0 or non 0 in this method.
Returns:
Tuple: (Imaginary part of self energy, sampling frequency points)
"""
if temperatures is None:
temperatures = [0.0, 300.0]
if temperatures is None:
print("Temperatures have to be set.")
return False
mesh = interaction.get_mesh_numbers()
ise = ImagSelfEnergy(interaction, in_details=write_details)
imag_self_energy = []
frequency_points = []
for i, gp in enumerate(grid_points):
ise.set_grid_point(gp)
if log_level:
weights = interaction.get_triplets_at_q()[1]
print("------------------- Imaginary part of self energy (%d/%d) "
"-------------------" % (i + 1, len(grid_points)))
print("Grid point: %d" % gp)
print("Number of ir-triplets: "
"%d / %d" % (len(weights), weights.sum()))
ise.run_interaction()
frequencies = interaction.get_phonons()[0]
max_phonon_freq = np.amax(frequencies)
if log_level:
adrs = interaction.get_grid_address()[gp]
q = adrs.astype('double') / mesh
print("q-point: %s" % q)
print("Phonon frequency:")
text = "[ "
for i, freq in enumerate(frequencies[gp]):
if i % 6 == 0 and i != 0:
text += "\n"
text += "%8.4f " % freq
text += "]"
print(text)
gamma_sigmas = []
fp_sigmas = []
if write_details:
triplets, weights, _, _ = interaction.get_triplets_at_q()
for j, sigma in enumerate(sigmas):
if log_level:
if sigma:
print("Sigma: %s" % sigma)
else:
print("Tetrahedron method")
ise.set_sigma(sigma)
if sigma:
fmax = max_phonon_freq * 2 + sigma * 4
else:
fmax = max_phonon_freq * 2
fmax *= 1.005
fmin = 0
frequency_points_at_sigma = get_frequency_points(
fmin,
fmax,
frequency_step=frequency_step,
num_frequency_points=num_frequency_points)
fp_sigmas.append(frequency_points_at_sigma)
gamma = np.zeros(
(len(temperatures), len(frequency_points_at_sigma),
len(interaction.get_band_indices())), dtype='double')
if write_details:
num_band0 = len(interaction.get_band_indices())
num_band = frequencies.shape[1]
detailed_gamma = np.zeros(
(len(temperatures), len(frequency_points_at_sigma),
num_band0, num_band, num_band, len(weights)),
dtype='double')
for k, freq_point in enumerate(frequency_points_at_sigma):
ise.set_frequency_points([freq_point])
if sigma is None or run_with_g:
ise.set_integration_weights(
scattering_event_class=scattering_event_class)
for l, t in enumerate(temperatures):
ise.set_temperature(t)
ise.run()
gamma[l, k] = ise.get_imag_self_energy()[0]
if write_details:
detailed_gamma[l, k] = np.transpose(
ise.get_detailed_imag_self_energy()[0],
axes=(1, 2, 3, 0))
gamma_sigmas.append(gamma)
if write_details:
filename = write_detailed_gamma_to_hdf5(
detailed_gamma,
temperatures,
mesh,
gp,
sigma,
triplets,
weights,
frequency_points=frequency_points_at_sigma)
if log_level:
print("Contribution of each triplet to imaginary part of "
"self energy is written in\n\"%s\"." % filename)
imag_self_energy.append(gamma_sigmas)
frequency_points.append(fp_sigmas)
return imag_self_energy, frequency_points
def get_linewidth(interaction,
grid_points,
sigmas,
temperatures=np.arange(0, 1001, 10, dtype='double'),
run_with_g=True,
write_details=False,
log_level=0):
ise = ImagSelfEnergy(interaction, in_details=write_details)
band_indices = interaction.get_band_indices()
mesh = interaction.get_mesh_numbers()
gamma = np.zeros(
(len(grid_points), len(sigmas), len(temperatures), len(band_indices)),
dtype='double')
for i, gp in enumerate(grid_points):
ise.set_grid_point(gp)
if log_level:
weights = interaction.get_triplets_at_q()[1]
print("------ Linewidth ------")
print("Grid point: %d" % gp)
print("Number of ir-triplets: "
"%d / %d" % (len(weights), weights.sum()))
ise.run_interaction()
frequencies = interaction.get_phonons()[0]
if log_level:
adrs = interaction.get_grid_address()[gp]
q = adrs.astype('double') / mesh
print("q-point: %s" % q)
print("Phonon frequency:")
print("%s" % frequencies[gp])
if write_details:
triplets, weights, _, _ = interaction.get_triplets_at_q()
for j, sigma in enumerate(sigmas):
if log_level:
if sigma:
print("Sigma: %s" % sigma)
else:
print("Tetrahedron method")
ise.set_sigma(sigma)
if sigma is None or run_with_g:
ise.set_integration_weights()
if write_details:
num_band0 = len(interaction.get_band_indices())
num_band = frequencies.shape[1]
num_temp = len(temperatures)
detailed_gamma = np.zeros(
(num_temp, num_band0, num_band, num_band, len(weights)),
dtype='double')
for k, t in enumerate(temperatures):
ise.set_temperature(t)
ise.run()
gamma[i, j, k] = ise.get_imag_self_energy()
if write_details:
detailed_gamma[k] = np.transpose(
ise.get_detailed_imag_self_energy(),
axes=(1, 2, 3, 0))
if write_details:
filename = write_detailed_gamma_to_hdf5(
detailed_gamma,
temperatures,
mesh,
gp,
sigma,
triplets,
weights)
if log_level:
print("Contribution of each triplet to imaginary part of "
"self energy is written in\n\"%s\"." % filename)
return gamma
