Transcript Document

Cohesive energy of ferroelectric material BaTiO3
HF orbital
DMC
30.1 +/- 0.3 eV
DFT/LDA orbital
DMC
31.3 +/- 0.3 eV
DFT(PW-91): 37.96 eV (20% off)
Exp:
31.57 eV
CDMC for optimization of geometries
-Scan force along an energy
path
-Fit to find minimum
of force
~10x faster than
discrete sampling
CDMC for geometries:
optimization of ferroelectric unit cell of BaTiO3
-Fix a=4.00 angstroms
-Ti is offset ~.06 A
-ferroelectric properties are
c very sensitive on accuracy
of tetragonal lattice const. c
a
Method
c (angstroms)
DFT(LDA)
DFT(PBE)
HF
DMC
Exp.
3.98
4.08
4.07
4.05(1)
4.04