material

Rb2MgF4

ID:

mp-8861

DOI:

10.17188/1312773


Tags: Dirubidium magnesium fluoride

Material Details

Final Magnetic Moment
0.000 μB

Calculated total magnetic moment for the unit cell within the magnetic ordering provided (see below). Typically accurate to the second digit.

Magnetic Ordering
Unknown
Formation Energy / Atom
-3.366 eV

Calculated formation energy from the elements normalized to per atom in the unit cell.

Energy Above Hull / Atom
0.000 eV

The energy of decomposition of this material into the set of most stable materials at this chemical composition, in eV/atom. Stability is tested against all potential chemical combinations that result in the material's composition. For example, a Co2O3 structure would be tested for decomposition against other Co2O3 structures, against Co and O2 mixtures, and against CoO and O2 mixtures.

Density
3.77 g/cm3

The calculated bulk crystalline density, typically underestimated due calculated cell volumes overestimated on average by 3% (+/- 6%)

Decomposes To
Stable
Band Gap
6.226 eV

In general, band gaps computed with common exchange-correlation functionals such as the LDA and GGA are severely underestimated. Typically the disagreement is reported to be ~50% in the literature. Some internal testing by the Materials Project supports these statements; typically, we find that band gaps are underestimated by ~40%. We additionally find that several known insulators are predicted to be metallic.

Space Group

Hermann Mauguin
I4/mmm [139]
Hall
-I 4 2
Point Group
4/mmm
Crystal System
tetragonal

Band Structure

Density of States
Warning! Semi-local DFT tends to severely underestimate bandgaps. Please see the wiki for more info.

sign indicates spin ↑ ↓

  • Cu
  • Ag
  • Mo
  • Fe

Calculated powder diffraction pattern; note that peak spacings may be affected due to inaccuracies in calculated cell volume, which is typically overestimated on average by 3% (+/- 6%)

X-Ray Absorption Spectra

FEFF XANES

Select an element to display a spectrum averaged over all sites of that element in the structure.

Apply Gaussian smoothing:

0 eV
3 eV
FWHM: 0 eV

Download spectra for every symmetrically equivalent absorption site in the structure.

Download FEFF Input parameters.

Warning: These results are intended to be semi-quantitative in that corrections, such as edge shifts and Debye-Waller damping, have not been included.

Substrates

Reference for minimal coincident interface area (MCIA) and elastic energy:
substrate orientation:
substrate material substrate orientation film orientation elastic energy [meV] MCIA [Å2]
SiC (mp-8062) <1 0 0> <0 0 1> 0.000 153.5
C (mp-66) <1 1 0> <1 0 1> 0.001 181.0
LiAlO2 (mp-3427) <0 0 1> <0 0 1> 0.002 136.4
ZnTe (mp-2176) <1 0 0> <0 0 1> 0.002 153.5
InAs (mp-20305) <1 0 0> <0 0 1> 0.005 153.5
Mg (mp-153) <1 1 1> <0 0 1> 0.005 272.8
TiO2 (mp-2657) <1 0 1> <1 0 0> 0.007 231.6
CdSe (mp-2691) <1 0 0> <0 0 1> 0.010 153.5
CsI (mp-614603) <1 0 0> <0 0 1> 0.010 306.9
Ga2O3 (mp-886) <1 0 -1> <0 0 1> 0.011 153.5
GaSb (mp-1156) <1 0 0> <0 0 1> 0.018 153.5
CdS (mp-672) <1 1 0> <1 0 1> 0.020 301.7
CaF2 (mp-2741) <1 0 0> <0 0 1> 0.020 153.5
SrTiO3 (mp-4651) <0 0 1> <0 0 1> 0.027 153.5
BN (mp-984) <1 0 0> <0 0 1> 0.027 289.9
PbSe (mp-2201) <1 0 0> <0 0 1> 0.030 153.5
LiTaO3 (mp-3666) <1 0 0> <1 0 0> 0.032 289.5
YAlO3 (mp-3792) <1 1 0> <0 0 1> 0.033 221.7
TePb (mp-19717) <1 0 0> <0 0 1> 0.035 85.3
LiGaO2 (mp-5854) <1 0 1> <0 0 1> 0.035 136.4
ZrO2 (mp-2858) <0 0 1> <0 0 1> 0.037 136.4
Ga2O3 (mp-886) <1 0 0> <1 1 0> 0.039 163.7
GaP (mp-2490) <1 0 0> <0 0 1> 0.040 153.5
GaTe (mp-542812) <1 0 -1> <0 0 1> 0.045 153.5
GaN (mp-804) <1 1 1> <0 0 1> 0.049 272.8
YAlO3 (mp-3792) <1 0 0> <0 0 1> 0.051 324.0
C (mp-66) <1 1 1> <0 0 1> 0.052 358.1
YAlO3 (mp-3792) <0 1 1> <0 0 1> 0.053 341.0
SrTiO3 (mp-4651) <1 1 0> <0 0 1> 0.057 306.9
CaCO3 (mp-3953) <0 0 1> <0 0 1> 0.058 358.1
Cu (mp-30) <1 1 1> <0 0 1> 0.059 358.1
Te2W (mp-22693) <0 1 0> <0 0 1> 0.060 324.0
GaSe (mp-1943) <0 0 1> <1 0 1> 0.062 241.4
Ag (mp-124) <1 0 0> <0 0 1> 0.062 17.1
TiO2 (mp-2657) <0 0 1> <0 0 1> 0.062 85.3
LaF3 (mp-905) <0 0 1> <1 0 1> 0.066 181.0
CdWO4 (mp-19387) <1 1 0> <0 0 1> 0.071 204.6
Te2Mo (mp-602) <0 0 1> <1 0 0> 0.076 173.7
WS2 (mp-224) <1 1 0> <1 0 0> 0.078 231.6
ZrO2 (mp-2858) <1 1 0> <0 0 1> 0.079 324.0
Ga2O3 (mp-886) <1 1 0> <0 0 1> 0.079 221.7
Bi2Se3 (mp-541837) <0 0 1> <1 0 1> 0.081 60.3
Fe2O3 (mp-24972) <1 0 0> <1 0 0> 0.082 289.5
SiC (mp-11714) <1 0 1> <0 0 1> 0.084 255.8
Ag (mp-124) <1 1 1> <0 0 1> 0.088 324.0
TiO2 (mp-390) <1 0 0> <0 0 1> 0.095 255.8
GaTe (mp-542812) <1 0 1> <1 0 0> 0.096 289.5
GaTe (mp-542812) <1 0 0> <0 0 1> 0.099 136.4
ZrO2 (mp-2858) <1 0 1> <0 0 1> 0.100 306.9
LiNbO3 (mp-3731) <1 0 0> <1 0 0> 0.101 289.5
Up to 50 entries displayed.
minimal coincident interface area.

Elasticity

Reference for tensor and properties:
Stiffness Tensor Cij (GPa)
75 27 23 0 0 0
27 75 23 0 0 0
23 23 66 0 0 0
0 0 0 15 0 0
0 0 0 0 15 0
0 0 0 0 0 33
Compliance Tensor Sij (10-12Pa-1)
16.3 -4.7 -4 0 0 0
-4.7 16.3 -4 0 0 0
-4 -4 17.9 0 0 0
0 0 0 68.5 0 0
0 0 0 0 68.5 0
0 0 0 0 0 30.3
Shear Modulus GV
22 GPa
Bulk Modulus KV
40 GPa
Shear Modulus GR
20 GPa
Bulk Modulus KR
40 GPa
Shear Modulus GVRH
21 GPa
Bulk Modulus KVRH
40 GPa
Elastic Anisotropy
0.53
Poisson's Ratio
0.28

Dielectric Properties

Reference for tensor and properties: Methodology
Dielectric Tensor εij (electronic contribution)
2.11 -0.00 -0.00
-0.00 2.11 -0.00
-0.00 -0.00 2.10
Dielectric Tensor εij (total)
6.76 -0.08 -0.27
-0.08 6.75 -0.30
-0.27 -0.30 5.87
Polycrystalline dielectric constant εpoly
(electronic contribution)
2.11
Polycrystalline dielectric constant εpoly
(total)
6.46
Refractive Index n
1.45
Potentially ferroelectric?
True

Calculation Summary

Elasticity

Methodology

Structure Optimization

Run Type
GGA
Energy Cutoff
520 eV
# of K-points
64
U Values
--
Pseudopotentials
VASP PAW: F Mg_pv Rb_sv
Final Energy/Atom
-4.6815 eV
Corrected Energy
-32.7708 eV
-32.7708 eV = -32.7708 eV (uncorrected energy)

Detailed input parameters and outputs for all calculations

User Data

dtu

Authors:
name conditions value ref
band gap
type
indirect
method
Kohn-Sham
functional
GLLB-SC
8.79 eV
band gap
type
direct
method
Kohn-Sham
functional
GLLB-SC
8.88 eV
band gap
type
indirect
method
quasiparticle
functional
GLLB-SC
12.14 eV
band gap
type
direct
method
quasiparticle
functional
GLLB-SC
12.22 eV
derivative discontinuity
functional
GLLB-SC
3.35 eV

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ICSD IDs
  • 69681

Displaying lattice parameters for primitive cell; note that calculated cell volumes are typically overestimated on average by 3% (+/- 6%). Note the primitive cell may appear less symmetric than the conventional cell representation (see "Structure Type" selector below the 3d structure)