Plasma freq corrected

libhreels/dielectrics20.py

@@ -4,25 +4,24 @@ import numpy as np
 from scipy import constants
 from scipy.integrate import cumulative_trapezoid
 
-def plasmaFrequency(n): 
-    '''Returns the plasma frequency for a given doping.'''
+def plasmaFrequency(n,eps_inf=1): 
+    '''Returns the plasma frequency for a given doping n in charge/m³.'''
     # Note that the function parameter is actually n/m, the charge carrier density 
     # over the band mass in units of electron mass in vacuum.
     eps_0 = constants.value("vacuum electric permittivity")
     e = constants.value('elementary charge')
     m_e = constants.value('electron mass')
-    w_P = np.sqrt(n*e*e/(eps_0*m_e)) #Hz
-    w_P = w_P /1E+12 * 33.35641 #Hz -> THz -> cm^-1
-    return w_P 
-    
-# def doping2chargecarrierdensity(doping): #use doping in percentage by mass, not volume
-#     '''Returns the charge carrier density for a given doping in percentage.'''
-#     return float(doping*3.31664067935517E+020*1E6) # doping[%] * charge carrier/cm^3 * 1E6 = n_e [m^-3] 
-
-# def doping2plasmaFrequency(doping): 
-#     '''Returns the plasma frequency for a given doping.'''
-#     n = doping2chargecarrierdensity(doping)
-#     return plasmaFrequency(n) 
+    # Careful: There is a factor of 2 pi between omega and nue:
+    # If the plasma oscillates in a polarisable medium eps_infinity will reduce the restoring fields
+    w_P = np.sqrt(n*e*e/(eps_0*eps_inf*m_e))        #
+    nue_P = w_P /1E+12 * 33.35641 /2 /np.pi   #Hz -> THz -> cm^-1
+    return nue_P
+
+def chargeDensitySTO(x):
+    # Calculates the charge density per m^3 for SrTi_(1-x)Nb_xO_3 
+    # assuming doping by one electron per Nb atom 
+    vol = 3.91*3.91*3.91 * 1E-30    # unit cell volume in m^3 
+    return x/vol
     
 
 def loss(eps):