1. Theory- ZnSb, ZnAs, Mg3Sb2 and Li2Sb Equations of State
Electron poor materials research group
Group meeting Oct. 7, 2010
Theory- ZnSb, ZnAs, Mg3Sb2 and Li2Sb Equations of State

2. Procedure Binary search of minimum pressure 6-8 cycles
each volume cycle contains 3 VASP runs
2 relaxation runs (back to back) and then a static run to get accurate energy values
6-8 cycles take 30min-24hours
each run is done in parallel on 3 cores.
Only PAW_GGA was calculated as of now
Values for the minimum volume V0, bulk modulus K0, minimum energy E0, and derivative of the bulk modulus K0p are then calculated from a 3rd order Birch-Murnaghan fit to the volume and free energy points obtained from the Volume cycles.

3. INCAR_relax System = InSb NSW = 5 | number of ionic steps
ISIF = | ISIF=4 relax cellshape and ions. NOT volume
IBRION = 1 | ionic relaxation algorithm
EDIFF = 1E-4 | break condition for elec. SCF loop
EDIFFG = -1E-3 | break condition for ionic relaxation loop
MAXMIX = | keep dielectric function between ionic movements
NELMIN = | minimum number of electronic steps
NFREE = | number of degrees of freedom (don't go above 20)
#RECOMMENDED MINIMUM SETUP
GGA=CA #xchange-correlation
VOSKOWN= #=1 if GGA=91; else = 0
PREC = NORMAL #PRECISION, sets fft grid
ENCUT = #energy cutoff, commented to use enmax in potcar
LREAL = .FALSE #.FALSE. MEANS USE RECIPROCAL LATTICE
ISMEAR = #0 means use gaussian smearing

4. INCAR_static System = InSb #ISTART = 0 # startjob: no WAVECAR file
#ICHARGE = 2 # charge: from atoms
#INIWAV = # random initialization for wf.
NELM = # maximum of 40 electronic steps
NELMIN = # minimum of 2 steps
NELMDL = # no update of charge for 3 steps
EDIFF = 1E-4 # accuracy for electronic minimization
#RECOMMENDED MINIMUM SETUP
GGA=CA #xchange-correlation
VOSKOWN= #=1 if GGA=91; else = 0
PREC = NORMAL #PRECISION, sets fft grid
ENCUT = #energy cutoff, commented to use enmax in potcar
LREAL = .FALSE #.FALSE. MEANS USE RECIPROCAL LATTICE
ISMEAR = #-5 means use tetrahedral with blochl

5. ZnSb Experimental Volume: 388.93 Run Time: ~ 22 Hours PAW-GGA E0 (eV)
Simulation time: ~22 hours
PAW-GGA
E0 (eV)
-42.83
V0 (Ang^3)
403.65
K0 (GPa)
48.55
K0p
5.63
Run Time:
~ 22 Hours

6. ZnAs Experimental Volume: 312.38 Run Time: ~ 20 Hours PAW-GGA E0 (eV)
Simulation time: ~22 hours
PAW-GGA
E0 (eV)
-48.64
V0 (Ang^3)
322.75
K0 (GPa)
62.79
K0p
4.43
Run Time:
~ 20 Hours

7. Mg3Sb2 Experimental Volume: 130.64 Run Time: ~ 16 Minutes PAW-GGA
Simulation time: ~22 hours
PAW-GGA
E0 (eV)
-14.90
V0 (Ang^3)
133.09
K0 (GPa)
42.14
K0p
5.27
Run Time:
~ 16 Minutes

8. Li2Sb Experimental Volume: 356.90 Run Time: ~ 2.5 hours PAW-GGA
Simulation time: ~22 hours
PAW-GGA
E0 (eV)
-58.45
V0 (Ang^3)
356.48
K0 (GPa)
39.33
K0p
42.5
Run Time:
~ 2.5 hours