material

K2Na4Ge2O7

ID:

mp-554107

DOI:

10.17188/1267740


Tags: Tetrasodium dipotassium digermanate

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
Non-magnetic
Formation Energy / Atom
-2.071 eV

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

Energy Above Hull / Atom
0.001 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
2.99 g/cm3

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

Decomposes To
Na4GeO4 + Na2GeO3 + K6Ge2O7
Band Gap
2.995 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
P21 [4]
Hall
P 2yb
Point Group
2
Crystal System
monoclinic

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]
Mg (mp-153) <1 1 0> <0 1 0> 0.007 289.1
Bi2Se3 (mp-541837) <0 0 1> <0 1 0> 0.007 289.1
NaCl (mp-22862) <1 1 1> <0 1 0> 0.008 224.8
ZrO2 (mp-2858) <1 0 -1> <0 1 0> 0.008 289.1
TePb (mp-19717) <1 1 1> <0 1 0> 0.010 224.8
SiC (mp-7631) <0 0 1> <0 1 0> 0.011 224.8
GaN (mp-804) <0 0 1> <0 1 0> 0.011 224.8
SiC (mp-11714) <0 0 1> <0 1 0> 0.012 224.8
C (mp-66) <1 1 1> <0 1 0> 0.013 289.1
ZnO (mp-2133) <0 0 1> <0 1 0> 0.014 289.1
Ni (mp-23) <1 0 0> <0 1 0> 0.015 257.0
CaCO3 (mp-3953) <0 0 1> <0 1 0> 0.016 289.1
YAlO3 (mp-3792) <0 1 1> <0 1 0> 0.016 96.4
CdS (mp-672) <0 0 1> <0 1 0> 0.022 289.1
MgO (mp-1265) <1 1 0> <0 1 0> 0.023 128.5
C (mp-48) <0 0 1> <0 1 0> 0.027 224.8
Bi2Te3 (mp-34202) <0 0 1> <0 1 0> 0.027 224.8
LaAlO3 (mp-2920) <1 0 1> <0 1 0> 0.033 224.8
CdWO4 (mp-19387) <1 0 1> <0 0 1> 0.039 179.6
PbS (mp-21276) <1 1 0> <0 1 0> 0.040 257.0
GaN (mp-804) <1 1 0> <0 1 0> 0.065 289.1
BN (mp-984) <1 0 1> <0 1 0> 0.069 224.8
BaTiO3 (mp-5986) <1 0 0> <0 1 0> 0.070 257.0
LiTaO3 (mp-3666) <1 0 0> <0 1 0> 0.075 289.1
CdTe (mp-406) <1 1 1> <0 1 0> 0.076 224.8
GaN (mp-804) <1 1 1> <0 1 1> 0.079 182.5
ZnSe (mp-1190) <1 1 1> <0 1 0> 0.081 224.8
PbS (mp-21276) <1 0 0> <0 0 1> 0.083 179.6
InSb (mp-20012) <1 1 1> <0 1 0> 0.088 224.8
ZrO2 (mp-2858) <1 0 0> <0 1 0> 0.090 224.8
Ni (mp-23) <1 1 0> <0 1 0> 0.091 257.0
Ga2O3 (mp-886) <1 0 0> <0 0 1> 0.098 179.6
AlN (mp-661) <0 0 1> <0 1 0> 0.099 224.8
Fe3O4 (mp-19306) <1 1 1> <0 1 0> 0.099 128.5
SiO2 (mp-6930) <0 0 1> <0 1 0> 0.102 289.1
GaAs (mp-2534) <1 1 1> <0 1 0> 0.108 224.8
LiNbO3 (mp-3731) <0 0 1> <0 1 0> 0.109 96.4
ZnO (mp-2133) <1 0 1> <0 1 0> 0.113 257.0
WS2 (mp-224) <0 0 1> <0 1 0> 0.113 224.8
MoS2 (mp-1434) <0 0 1> <0 1 0> 0.113 224.8
Ga2O3 (mp-886) <1 0 1> <1 0 -1> 0.117 180.8
InP (mp-20351) <1 0 0> <0 0 1> 0.118 179.6
Te2W (mp-22693) <0 0 1> <0 1 0> 0.125 353.3
SiC (mp-7631) <1 1 0> <0 1 0> 0.133 160.6
C (mp-66) <1 1 0> <0 1 0> 0.142 289.1
Mg (mp-153) <1 1 1> <0 1 1> 0.144 182.5
BN (mp-984) <1 0 0> <0 1 0> 0.148 353.3
MgO (mp-1265) <1 1 1> <0 1 0> 0.152 32.1
TiO2 (mp-2657) <1 0 0> <0 1 0> 0.156 224.8
Ge (mp-32) <1 1 1> <0 1 0> 0.161 224.8
Up to 50 entries displayed.
minimal coincident interface area.

Elasticity

Reference for tensor and properties:
Stiffness Tensor Cij (GPa)
78 27 32 0 1 0
27 81 28 0 2 0
32 28 82 0 -0 0
0 0 0 22 0 1
1 2 -0 0 24 0
0 0 0 1 0 18
Compliance Tensor Sij (10-12Pa-1)
16.1 -3.5 -5.1 0 -0.2 0
-3.5 14.8 -3.6 0 -0.9 0
-5.1 -3.6 15.4 0 0.6 0
0 0 0 45.1 0 -3.2
-0.2 -0.9 0.6 0 41.7 0
0 0 0 -3.2 0 56.1
Shear Modulus GV
23 GPa
Bulk Modulus KV
46 GPa
Shear Modulus GR
23 GPa
Bulk Modulus KR
46 GPa
Shear Modulus GVRH
23 GPa
Bulk Modulus KVRH
46 GPa
Elastic Anisotropy
0.12
Poisson's Ratio
0.29

Calculation Summary

Elasticity

Methodology

Structure Optimization

Run Type
GGA
Energy Cutoff
520 eV
# of K-points
20
U Values
--
Pseudopotentials
VASP PAW: K_sv Na_pv Ge_d O
Final Energy/Atom
-5.1600 eV
Corrected Energy
-329.2612 eV
-329.2612 eV = -309.5971 eV (uncorrected energy) - 19.6641 eV (MP Anion Correction)

Detailed input parameters and outputs for all calculations


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ICSD IDs
  • 62650

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)