def polarizability(base_dir="./", mode="df", fermi_shift=None):
curr_dir = os.path.dirname(os.path.abspath(__file__))
es_gpw = os.path.join(base_dir, "es.gpw")
param_file = os.path.join(curr_dir, "../parameters.json")
if os.path.exists(param_file):
params = json.load(open(param_file, "r"))
else:
raise FileNotFoundError("no parameter file!")
if not os.path.exists(es_gpw):
raise FileNotFoundError("Excited state not calculated!")
if mode not in ("df", "tetra"):
raise ValueError("Mode should be df or tetra")
if fermi_shift is None:
data_file = os.path.join(base_dir,
"polarizability_{}.npz".format(mode))
else:
data_file = os.path.join(base_dir,
"polarizability_{}_{:.2f}.npz".format(mode, fermi_shift))
params[mode]["intraband"] = True
if os.path.exists(data_file):
parprint("Polarizability file exists!")
return 0
df = DielectricFunction(calc=es_gpw,
**params[mode],
gate_voltage=fermi_shift) # add energy shift
alpha0x, alphax = df.get_polarizability(q_c=[0, 0, 0],
direction="x",
pbc=[True, True, False],
filename=None)
alpha0y, alphay = df.get_polarizability(q_c=[0, 0, 0],
direction="y",
pbc=[True, True, False],
filename=None)
alpha0z, alphaz = df.get_polarizability(q_c=[0, 0, 0],
direction="z",
pbc=[True, True, False],
filename=None)
freq = df.get_frequencies()
data = dict(frequencies=freq,
alpha_x=alphax,
alpha_y=alphay,
alpha_z=alphaz,
alpha_x0=alpha0x,
alpha_y0=alpha0y,
alpha_z0=alpha0z,)
from ase.parallel import world
import numpy
if world.rank == 0:
numpy.savez_compressed(data_file, **data)
def permittivity(base_dir="./", mode="df"):
curr_dir = os.path.dirname(os.path.abspath(__file__))
es_gpw = os.path.join(base_dir, "es.gpw")
param_file = os.path.join(curr_dir, "../parameters.json")
if os.path.exists(param_file):
params = json.load(open(param_file, "r"))
else:
raise FileNotFoundError("no parameter file!")
if not os.path.exists(es_gpw):
raise FileNotFoundError("Excited state not calculated!")
if mode not in ("df", "tetra"):
raise ValueError("Mode should be df or tetra")
data_file = os.path.join(base_dir, "polarizability_{}.npz".format(mode))
if os.path.exists(data_file):
parprint("Polarizability file exists!")
return 0
df = DielectricFunction(calc=es_gpw, **params[mode])
eps0x, epsx = df.get_dielectric_function(
q_c=[0, 0, 0],
direction="x",
#pbc=[True, True, False],
filename=None)
eps0y, epsy = df.get_dielectric_function(
q_c=[0, 0, 0],
direction="y",
#pbc=[True, True, False],
filename=None)
eps0z, epsz = df.get_dielectric_function(
q_c=[0, 0, 0],
direction="z",
#pbc=[True, True, False],
filename=None)
freq = df.get_frequencies()
data = dict(
frequencies=freq,
eps_x=epsx,
eps_y=epsy,
eps_z=epsz,
eps_x0=eps0x,
eps_y0=eps0y,
eps_z0=eps0z,
)
from ase.parallel import world
import numpy
if world.rank == 0:
numpy.savez_compressed(data_file, **data)
def get_hydrogen_chain_dielectric_function(NH, NK):
a = Atoms('H', cell=[1, 1, 1], pbc=True)
a.center()
a = a.repeat((1, 1, NH))
a.calc = GPAW(mode=PW(200), kpts={'size': (1, 1, NK), 'gamma': True},
parallel={'band': 1}, dtype=complex, gpts=(10, 10, 10 * NH))
a.get_potential_energy()
a.calc.diagonalize_full_hamiltonian(nbands=2 * NH)
a.calc.write('H_chain.gpw', 'all')
DF = DielectricFunction('H_chain.gpw', ecut=1e-3, hilbert=False,
omega2=np.inf, intraband=False)
eps_NLF, eps_LF = DF.get_dielectric_function(direction='z')
omega_w = DF.get_frequencies()
return omega_w, eps_LF
def get_hydrogen_chain_dielectric_function(NH, NK):
a = Atoms('H', cell=[1, 1, 1], pbc=True)
a.center()
a = a.repeat((1, 1, NH))
a.calc = GPAW(mode=PW(200, force_complex_dtype=True),
kpts={'size': (1, 1, NK), 'gamma': True},
parallel={'band': 1},
gpts=(10, 10, 10 * NH))
a.get_potential_energy()
a.calc.diagonalize_full_hamiltonian(nbands=2 * NH)
a.calc.write('H_chain.gpw', 'all')
DF = DielectricFunction('H_chain.gpw', ecut=1e-3, hilbert=False,
omega2=np.inf, intraband=False)
eps_NLF, eps_LF = DF.get_dielectric_function(direction='z')
omega_w = DF.get_frequencies()
return omega_w, eps_LF
def dielectric(self, method="rpa"):
method = method.lower()
if method not in ("rpa", "gw"):
raise ValueError("Dielectric Method not known!")
if not os.path.exists(self.__es_file):
raise FileNotFoundError("Ground state not calculated!")
self.__eps_file = self.__eps_file_template.format(method)
if os.path.exists(self.__eps_file):
parprint(("Dielectricfunction using"
" method {} already calculated!").format(method))
return True
if os.path.exists(self.__es_file):
parprint("Excited state done, will use directly!")
if method == "rpa":
df = DielectricFunction(calc=self.__es_file, **self.params[method])
epsx0, epsx = df.get_dielectric_function(direction="x",
filename=None)
epsy0, epsy = df.get_dielectric_function(direction="y",
filename=None)
epsz0, epsz = df.get_dielectric_function(direction="z",
filename=None)
freq = df.get_frequencies()
data = dict(frequencies=freq,
eps_x=epsx,
eps_x0=epsx0,
eps_y=epsy,
eps_y0=epsy0,
eps_z=epsz,
eps_z0=epsz)
# write result
if rank == 0:
numpy.savez(self.__eps_file, **data)
parprint("Dielectric function using {} calculated!".format(method))
return True
else:
raise NotImplementedError("{} not implemented".format(method))
responseGS.get_potential_energy()
responseGS.write('TaS2-gsresponse.gpw', 'all')
# 3) Dielectric function
df = DielectricFunction('TaS2-gsresponse.gpw',
eta=25e-3,
domega0=0.01,
integrationmode='tetrahedron integration')
df1tetra_w, df2tetra_w = df.get_dielectric_function(direction='x')
df = DielectricFunction('TaS2-gsresponse.gpw', eta=25e-3, domega0=0.01)
df1_w, df2_w = df.get_dielectric_function(direction='x')
omega_w = df.get_frequencies()
if world.rank == 0:
plt.figure(figsize=(6, 6))
plt.plot(omega_w, df2tetra_w.real, label='tetra Re')
plt.plot(omega_w, df2tetra_w.imag, label='tetra Im')
plt.plot(omega_w, df2_w.real, label='Re')
plt.plot(omega_w, df2_w.imag, label='Im')
plt.xlabel('Frequency (eV)')
plt.ylabel('$\\varepsilon$')
plt.xlim(0, 10)
plt.ylim(-20, 20)
plt.legend()
plt.tight_layout()
plt.savefig('tas2_eps.png', dpi=600)
# plt.show()
