Self-consistent (SC) and range-separated (RS) functionals
The generalized Kohn-Sham potential ($GKS$) is given by the sum of the Hartree ($H$), exchange ($x$), correlation ($c$) and external ($ext$) potentials:
where
and
and
$\rho$ is the density matrix and $\mu$ is chosen as:
or
Here $n_v$ is the number of valence electrons; we also considered $\mu$ = $\mu_{PDEP}$ = long range decay of the diagonal elements of the dielectric matrix.
Note that:
Functional | α | β | μ (bohr-1) |
---|---|---|---|
PBE | 0 | 0 | 0 |
EXXc | 1 | 0 | ∞ |
PBE0 | 0.25 | 0 | ∞ |
SC Hybrid | 1/ϵ∞ | 0 | ∞ |
HSE06 | 0 | 0.25 | 0.11 |
sX-LDA | 0 | 1 | Thomas-Fermi |
CAM-B3LYP | 0.46 | 0.19 | 0.33 |
LC-μPBE | 1 | 0 | 0.4 |
TABLE I. The dielectric constants (ϵ∞) determined self-consistently as described in Skone et al. 2014 for the set of semiconductors and insulators listed in the first column is given in column 2. The screening parameters (μ) used in the RSH functional form proposed in Skone et al. 2016 are listed in units of bohr-1 in columns 3-6.
μPDEP | |||||
---|---|---|---|---|---|
ϵ∞ | μWS | μTF | μerfc-fit | μTF-fit | |
Si | 11.76 | 0.50 | 0.55 | 0.64 | 0.64 |
AlP | 7.23 | 0.50 | 0.55 | 0.65 | 0.64 |
SiC | 6.50 | 0.62 | 0.62 | 0.77 | 0.77 |
TiO2 | 6.56 | 0.68 | 0.65 | ||
NiO | 5.49 | 0.82 | 0.71 | ||
C | 5.61 | 0.76 | 0.68 | 0.93 | 0.97 |
CoO | 4.92 | 0.78 | 0.69 | ||
GaN2 | 5.14 | 0.60 | 0.61 | ||
ZnS | 4.95 | 0.65 | 0.63 | ||
MnO | 4.45 | 0.72 | 0.66 | ||
WO3 | 4.72 | 0.66 | 0.63 | ||
BN | 4.40 | 0.75 | 0.68 | 0.91 | 0.95 |
HfO2 | 3.97 | 0.66 | 0.63 | ||
AlN | 4.16 | 0.49 | 0.55 | ||
ZnO | 3.46 | 0.78 | 0.69 | ||
Al2O3 | 3.01 | 0.71 | 0.66 | ||
MgO | 2.81 | 0.64 | 0.63 | ||
LiCl | 2.77 | 0.53 | 0.57 | ||
NaCl | 2.29 | 0.49 | 0.54 | 0.63 | 0.64 |
LiF | 1.86 | 0.68 | 0.64 | 0.80 | 0.83 |
H2O2 | 1.68 | 0.55 | 0.58 | 0.52 | 0.53 |
Ar | 1.66 | 0.52 | 0.56 | 0.72 | 0.73 |
Ne | 1.21 | 0.61 | 0.61 | 0.83 | 0.89 |
TABLE II. The Kohn-Sham (KS) energy gaps (eV) evaluated with hybrid functionals are compared with the experimental (Exp.) electronic gaps for a wide range of semiconductors and insulators. The experimental values correspond to either photoemission measurements or to optical measurements where the excitonic contributions were removed, with alumina being the only exception. The KS gaps were computed as the single-particle energy difference of the conduction band minimum and the valence band maximum. The sc-hybrid heading refers to hybrid calculations where the fraction of exact exchange is the self-consistent ϵ∞ (see Skone et al. 2014). The RSH columns correspond to the electronic gap evaluated with the range separation scheme described in Skone et al. 2016 from Shishkin et al.. ME, MAE, MRE, and MARE are the mean, mean absolute, mean relative, and mean absolute relative error, respectively. The experimental geometry was used in all calculations. Note that CoO, NiO, and MnO are magnetic with AFM-II magnetic ordering. The structure/polytype used for each system is the same as Table I of Skone et al. 2014.
PBE0 | sc-hybrid | RSH μWS | RSH μTF | RSH μerfc-fit | scGW [62] | Exp. | |
---|---|---|---|---|---|---|---|
Si | 1.75 | 0.99 | 1.03 | 1.02 | 1.01 | 1.24 | 1.17 [see C. Kittel, Introduction to Solid State Physics (Wiley, NewYork, 2005)] |
AlP | 2.98 | 2.37 | 2.43 | 2.42 | 2.40 | 2.57 | 2.51 [Ref.] |
SiC | 2.91 | 2.29 | 2.32 | 3.32 | 2.31 | 2.53 | 2.39 [Ref.] |
TiO2 | 3.05 | 3.16 | 0.65 | 3.17 | 3.3 [Ref.] | ||
NiO | 5.28 | 4.11 | 4.45 | 4.3 [Ref.] | |||
C | 5.95 | 5.42 | 5.44 | 5.45 | 5.43 | 5.79 | 5.48 [Ref.]a |
CoO | 4.53 | 3.62 | 3.92 | 3.98 | 2.5 [Ref.] | ||
GaN2 | 3.26 | 3.30 | 0.61 | 3.30 | 3.27 | 3.29 [Ref.] | |
ZnS | 4.18 | 3.82 | 3.85 | 3.86 | 3.60 | 3.91 [see C. Kittel, Introduction to Solid State Physics (Wiley, NewYork, 2005)] | |
MnO | 3.87 | 3.60 | 3.65 | 3.49 | 3.9 [Ref.] | ||
WO3 | 3.76 | 3.47 | 3.49 | 3.49 | 3.38 [Ref.] | ||
BN | 6.51 | 6.33 | 6.33 | 6.33 | 6.33 | 6.59 | 6.4 [see M. Levinshtein et al., Properties of Advanced Semiconductor Materials: GaN, AlN, InN, BN, SiC, and SiGe (Wiley, New York, 2001)] |
HfO2 | 6.65 | 6.68 | 6.67 | 6.67 | 5.84 [Ref.] | ||
AlN | 6.31 | 6.23 | 6.22 | 6.23 | 6.28 [Ref.] | ||
ZnO | 3.41 | 3.78 | 3.75 | 3.2 | 3.44 [Ref.] | ||
Al2O3 | 8.84 | 9.71 | 9.63 | 9.61 | 8.8 [Ref.] | ||
MgO | 7.25 | 8.33 | 8.23 | 8.22 | 8.27 | 8.12 | 7.83 [Ref.] |
LiCl | 8.66 | 9.62 | 9.52 | 9.54 | 9.4 [Ref.] | ||
NaCl | 7.26 | 8.84 | 8.60 | 8.66 | 8.71 | 8.6 [Ref.] | |
LiF | 12.18 | 15.69 | 15.24 | 15.18 | 15.42 | 14.5 | 14.2 [Ref.] |
H2O2 | 7.92 | 11.49 | 10.89 | 10.94 | 10.84 | 10.9 [Ref.] | |
Ar | 11.20 | 14.67 | 14.12 | 14.20 | 14.41 | 13.9 | 14.2 [Ref.] |
Ne | 15.20 | 23.67 | 21.44 | 21.44 | 22.28 | 21.4 | 21.7 [Ref.] |
ME (eV) | -0.40 | 0.32 | 0.18 | 0.19 | |||
MAE (eV) | 1.08 | 0.42 | 0.29 | 0.30 | |||
MRE (%) | 6.2 | 3.7 | 3.4 | 3.5 | |||
MARE (%) | 17.1 | 7.5 | 6.4 | 6.5 |
aThe exp. QP gap reported here does not account for the zero-point vibrational gap renormalization, which has been shown to be non-negligible for diamond (see Cardona, Giustino et al., and van Elp et al..
TABLE III. The dielectric constant (ϵ∞) determined self-consistently as described in Skone et al. 2014 for the set of molecular crystals listed in the first column is given in column 2. The screening parameters (μ) usd in the RSH functional form (see Skone et al. 2016) of Eq. (17) are listed in units of bohr-1 in columns 3 and 4. All μ have units of bohr-1.
Crystalline | |||
---|---|---|---|
ϵ∞ | μTF | μerfc-fit | |
C14H8S4-C12H4N4 (DBTTF-TCNQ) | 11.07 | 0.58 | |
C60 (buckminsterfullerene) | 4.29 | 0.61 | 0.57 |
C32H18N8 (phthalocyanine) | 3.97 | 0.60 | |
C24H8O6 (α-PTCDA) | 3.45 | 0.61 | |
C22H14 (pentacene) | 3.36 | 0.59 | |
C20H12O2 (β-quinacridone) | 3.15 | 0.60 | |
C18H12 (tetracene) | 3.15 | 0.59 | |
C14H10 (anthracene) | 3.02 | 0.58 | |
C42H28 (rubrene) | 2.88 | 0.58 | 0.50 |
C10H8 (naphthalene) | 2.70 | 0.58 | |
C6H6 (benzene) | 2.40 | 0.57 | 0.54 |
NH3 (ammonia) | 2.00 | 0.57 | 0.53 |
C2H4O2 (acetic acid) | 1.88 | 0.60 | |
H2O (ice) | 1.68 | 0.58 | 0.52 |
TABLE IV. The xx, yy, zz components of the dielectric tensor (ϵ∞) of the systems listed on the first row, computed at the PBE, PBE0, and sc-hybrid levels of theory, and the corresponding experimental results.
Anthracene | PTCDA | DBTTF-TCNQ | |||||||
---|---|---|---|---|---|---|---|---|---|
ϵxx | ϵyy | ϵzz | ϵxx | ϵyy | ϵzz | ϵxx | ϵyy | ϵzz | |
PBE | 2.28 | 2.93 | 4.30 | 2.25 | 4.40 | 4.50 | 42.38 | 3.67 | 2.90 |
PBE0 | 2.22 | 2.83 | 4.10 | 2.12 | 4.10 | 4.12 | 11.08 | 5.82 | 2.72 |
sc-hybrid | 2.21 | 2.80 | 4.02 | 2.11 | 4.06 | 4.08 | 26.28 | 3.54 | 2.81 |
Exp. [Cummins et al. 1974, Alonso et al. 2002] | 2.42 ± 0.05 | 2.90 ± 0.05 | 4.07 ± 0.05 | 2.40 | 5.29 | 5.02 | |||
Exp. [Munn et al. 1973, Zang et al. 1991] | 2.62 ± 0.03 | 2.94 ± 0.03 | 4.08 ± 0.03 | 1.90 | 4.09 | ||||
Exp. [Karl et al. 1971, Fuchigami et al. 1995] | 2.51 | 2.99 | 4.11 | 2.28 | 3.73 |
TABLE V. The Kohn-Sham (KS) energy gaps (eV) evaluated with the dielectric-dependent hybrid functionals PBE and PBE0 are compared with the experimental electronic gaps for several molecular crystals. The experimental values are from photoemission measurements.
PBE α=0 | PBE0 α=0.25 | Hybrid α=1/ϵPBE∞ | Hybrid α=1/ϵPBE0∞ | Hybrid α=1/ϵsc∞ | RSH μTF | Exp. | |
---|---|---|---|---|---|---|---|
DBTTF-TCNQ | 0.16 | 0.74 | 0.26 | 0.45 | 0.31 | 0.33 | |
C60 | 1.27 | 2.34 | 2.11 | 2.27 | 2.26 | 2.26 | 2.3 ± 0.1 [Ref.] |
phthalocyanine (H2Pc) | 1.22 | 1.85 | 1.84 | 1.85 | 1.85 | 1.85 | 2.2 ± 0.2 [Ref.] |
PTCDA | 1.41 | 2.53 | 2.62 | 2.72 | 2.73 | 2.73 | 2.74 ± 0.2 [Ref.] |
pentacene | 0.76 | 1.83 | 1.95 | 2.04 | 2.05 | 2.05 | 2.1 [Ref., Ref.] |
quinacridone | 1.43 | 2.76 | 3.02 | 3.13 | 3.13 | 3.11 | |
tetracene | 1.26 | 2.46 | 2.72 | 2.78 | 2.80 | 2.79 | 3.3 [Ref., Ref.] |
anthracene | 2.05 | 3.45 | 3.82 | 3.89 | 3.91 | 3.89 | 3.72 [Ref.] |
rubrene | 1.15 | 2.32 | 2.70 | 2.77 | 2.79 | 2.77 | 2.67 [Ref.] |
naphthalene | 3.05 | 4.64 | 5.32 | 5.39 | 5.41 | 5.37 | 5.29 [Ref., Ref.] |
benzene | 4.57 | 6.37 | 7.48 | 7.56 | 7.58 | 7.47 | 7.58 [Ref., Ref.] |
ammonia | 4.52 | 6.82 | 8.76 | 9.00 | 9.17 | 8.92 | |
acetic acid | 5.18 | 7.96 | 10.76 | 10.95 | 11.12 | 10.62 | |
H2O (icea) | 5.42 | 7.92 | 10.96 | 11.23 | 11.49 | 10.94 | 10.9 [Ref.] |
ME (eV) | -2.05 | -0.69 | -0.12 | -0.02 | 0.02 | -0.06 | |
MAE (eV) | 2.05 | 0.70 | 0.19 | 0.18 | 0.21 | 0.16 | |
MRE (%) | -49.6 | -13.5 | -4.9 | -2.3 | -1.7 | -2.6 | |
MARE (%) | 49.6 | 13.8 | 6.1 | 5.1 | 5.4 | 4.9 |
aSee the Supplemental Material of Skone et al. 2016 for details on the cell of ice used. The experimental photoemission gap shown is for proton-disordered ice Ih at 80 K.
TABLE VI. The vertical ionization potential (vIPs), in units of eV, of several solid molecular crystals evaluated with PBE, PBE0, sc-hybrid ans RSH functionals. The experimental values are listed for comparison. Note that for rubrene the surface listed corresponds to the orthorhombic cell. The screening parameters μTF and μαM are defined in (see Skone et al. 2016) Eq. (9) and Eq. (13), respectively.
surface | PBE | PBE0 | sc-hybrid | RSH μTF | Exp. | |
---|---|---|---|---|---|---|
rubrene | (100) | 3.85 | 4.45 | 4.69 | 4.68 | 4.85 [Ref.] |
benzene | (001) | 6.08 | 7.02 | 7.63 | 7.61 | 7.58 [Ref.] |
icea | (1010) | 7.2 | 8.7 | 11.2 | 10.7 | 11.8 [Ref., and D. Nordlund, H. Ogasawara, and A. Nilsson, Maxlab Annual Report, p. 236, 2001] |
aThe prism surface of ice is used. See Pan et al. [Ref.] for further details on the common surfaces of ice.
TABLE VII. Screening parameters for isolated molecules. The second and third columns list the screening parameters obtained from the fit of the RPA dielectric function of the isolated molecules and obtained from the molecular polarizability radius [see Eq. (13) of Skone et al. 2016. We also give in column 4 the screening parameters obtained from the OT-RSH functional defined in Refaely-Abramson et al..
μerfc-fit | μαM | μOT-RSH | |
---|---|---|---|
C60 (buckminsterfullerene) | 0.64 | 0.12 | 0.14 |
C24H8O6 (α-PTCDA) | 0.62 | 0.14 | 0.14 |
C22H14 (pentacene) | 0.56 | 0.14 | 0.15 |
C20H12O2 (β-quinacridone) | 0.59 | 0.15 | 0.15 |
C18H12 (tetracene) | 0.58 | 0.16 | 0.16 |
C14H10 (anthracene) | 0.59 | 0.18 | 0.18 |
C42H28 (rubrene) | 0.61 | 0.12 | 0.11 |
C10H8 (naphthalene) | 0.61 | 0.21 | 0.21 |
C6H6 (benzene) | 0.63 | 0.24 | 0.21 |
NH3 (ammonia) | 0.63 | 0.40 | 0.33 |
C2H4O2 (acetic acid) | 0.69 | 0.31 | 0.27 |
H2O (water) | 0.67 | 0.46 | 0.38 |
TABLE VIII. The gas phase vertical ionization potential (vIPs), in units of eV, of several molecules that compose the molecular crystals evaluated using the RSH-DDH with μ = μerfc-fit and μ = μαM, are shown in column 2 and column 3, respectively. Also shown are values determined by using the OT-RSH functional defined in Refaely-Abramson et al., column 4. The experimental values (Exp.), taken from the NIST WebBook [see Linstrom et al., NIST Chemistry WebBook, NIST Standard Reference Database No. 69 (National Institute of Standards and Technology), Gaithersburg, MD, 2001], are listed in column 5.
vIPg (eV) | ||||
---|---|---|---|---|
RSH μerfc-fit | RSH μαM | RSH μOT-RSH | Exp. | |
C60 | 8.74 | 7.40 | 7.76 | 7.60 |
PTCDA | 9.23 | 8.20 | 8.20 | 8.20 |
pentacene | 7.08 | 6.29 | 6.29 | 6.61 |
quinacridone | 8.44 | 7.35 | 7.35 | 7.23 |
tetracene | 7.51 | 6.72 | 6.72 | 6.97 |
anthracene | 8.14 | 7.30 | 7.30 | 7.44 |
rubrene | 7.28 | 6.28 | 6.16 | 6.52 |
naphthalene | 8.87 | 8.07 | 8.07 | 8.14 |
benzene | 10.15 | 9.37 | 9.24 | 9.25 |
ammonia | 11.85 | 11.07 | 10.7 | 10.8 |
acetic acid | 12.61 | 11.08 | 10.78 | 10.9 |
H2O | 13.78 | 13.01 | 12.55 | 12.62 |
ME (eV) | 0.95 | -0.01 | -0.10 | |
MAE (eV) | 0.95 | 0.19 | 0.14 | |
MRE (%) | 11.1 | -0.6 | -1.3 | |
MARE (%) | 11.1 | 2.3 | 1.9 |
Method | MAE [eV] |
---|---|
G0W0@PBE0 | 0.19 |
SX | 0.28 |
G0W0@SX | 0.38 |
G0W0@PBE | 0.44 |
EXXc | 1.50 |
B3LYP | 2.78 |
PBE0 | 2.87 |
HSE06 | 3.27 |
PBE (ΔSCF) | 4.29 (0.24) |
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