******************************************************************************
*                                                                            *
*          ABINIT tutorial: nonlinear response, Berry phase                  *
*                           & finite electric fields                         *
*                                                                            *
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1) Parameters used in all calculations
--------------------------------------
   system		AlAs
   code			ABINITv4.4.4

   acell		theoretical lattice constant computed for the 
			same k-point grid as the corresponding response 
                        properties
   ixc			3
   ecut			5
   ecutsm		0.5
   dilatmx		1.05
   nbdbuf		0
   nshiftk		4
   nband		4 (number of occupied bands)

   pseudopotentials	13al.pspnc
			33as.pspnc


2) Structural optimizations
---------------------------

===================================
  ngkpt		       acell
-----------------------------------
 6  6  6	10.6395177524329601
 8  8  8	10.6396307919372131
10 10 10	10.6396442853730768
12 12 12	10.6397077264277993
14 14 14	10.6396719133078097
16 16 16	10.6396728602652111
===================================


3) Density functional perturbation theory calculations
------------------------------------------------------

3A) NGKPT 6 6 6
---------------
Born effective charge of Al: Z* = 2.105999E+00
Nonlinear optical susceptibility (pm/V): d = 32.772254
d chi / d tau (Bohr^-1) of Al = -0.099889084
w_TO (cm^-1) = 3.602635E+02
w_LO (cm^-1) = 3.931598E+02
Electronic dielectric tensor = 9.94846084
Relaxed ion dielectric tensor = 11.84823634
Proper piezoelectric constants(clamped ion)(Unit:c/m^2) = -0.69401363
Proper piezoelectric constants(relaxed ion)(Unit:c/m^2) = -0.04228777
Electronic EO constant (pm/V): -1.324507791
Ionic EO constant (pm/V): 0.533097548
Total EO constant (pm/V): -0.791410242

Faust-Henry coefficient: C = -0.4024874
Raman polarizability (A^2):
        ato = -8.4222112
        alo = -12.418168

Finite difference calculation: d chi / d tau (Bohr^-1) of Al = -0.1066171

4) Ground-state Berry phase calculations
----------------------------------------

Finite differences of the polarization w.r.t. atomic displacements
Born effective charge of Al: Z* = 2.1273874

Finite difference calculation of the ddk
Born effective charge of Al: Z* = 2.1273577300
Proper piezoelectric constants(clamped ion)(Unit:c/m^2) = -0.69084784
Proper piezoelectric constants(relaxed ion)(Unit:c/m^2) = -0.03251216

Finite differences of the polarization w.r.t. strain
Proper piezoelectric constants(clamped ion)(Unit:c/m^2) = -0.6909505
Proper piezoelectric constants(relaxed ion)(Unit:c/m^2) = -0.0326305

5) Finite electric field calculations
-------------------------------------
Electronic dielectric constant: 8.72523139872855
Nonlinear optical susceptibility (pm/V): d = 29.7685679334192
Born effective charge of Al: 2.12729059075091
d chi / d tau (Bohr^-1) of Al = -0.0616968881813368

Static dielectric constant: 10.665771361062

Proper piezoelectric constants(clamped ion)(Unit:c/m^2) = -0.690881351221756
Proper piezoelectric constants(relaxed ion)(Unit:c/m^2) = -0.0325937630208201
