material

KNbSe2

ID:

mp-7940

DOI:

10.17188/1307849


Tags: Potassium niobium selenide (.7/1/2)

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
-0.986 eV

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

Energy Above Hull / Atom
0.015 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
5.13 g/cm3

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

Decomposes To
Nb3Se4 + Nb2Se + K3NbSe4
Band Gap
0.686 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
P63/mmc [194]
Hall
-P 6c 2c
Point Group
6/mmm
Crystal System
hexagonal

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%)

Substrates

Reference for minimal coincident interface area (MCIA) and elastic energy:
substrate orientation:
substrate material substrate orientation film orientation elastic energy [meV] MCIA [Å2]
Ni (mp-23) <1 1 1> <0 0 1> 0.002 148.9
Ge(Bi3O5)4 (mp-23352) <1 1 1> <0 0 1> 0.002 183.3
Al2O3 (mp-1143) <0 0 1> <0 0 1> 0.004 80.2
CdS (mp-672) <0 0 1> <0 0 1> 0.006 45.8
Bi2Se3 (mp-541837) <0 0 1> <0 0 1> 0.008 45.8
InP (mp-20351) <1 1 1> <0 0 1> 0.018 183.3
Cu (mp-30) <1 0 0> <0 0 1> 0.028 91.6
LiGaO2 (mp-5854) <1 0 1> <1 0 0> 0.028 178.6
BN (mp-984) <0 0 1> <0 0 1> 0.029 103.1
LaF3 (mp-905) <0 0 1> <0 0 1> 0.030 45.8
AlN (mp-661) <1 0 0> <0 0 1> 0.033 126.0
Au (mp-81) <1 0 0> <0 0 1> 0.034 366.6
Te2W (mp-22693) <1 1 1> <0 0 1> 0.036 114.6
Si (mp-149) <1 0 0> <0 0 1> 0.043 240.6
BaF2 (mp-1029) <1 0 0> <0 0 1> 0.044 274.9
MgO (mp-1265) <1 1 1> <0 0 1> 0.044 217.7
CeO2 (mp-20194) <1 0 0> <0 0 1> 0.046 240.6
NdGaO3 (mp-3196) <0 1 0> <0 0 1> 0.061 171.8
GaP (mp-2490) <1 0 0> <0 0 1> 0.064 240.6
Mg (mp-153) <1 1 1> <0 0 1> 0.082 240.6
YVO4 (mp-19133) <1 0 0> <0 0 1> 0.091 45.8
AlN (mp-661) <0 0 1> <0 0 1> 0.094 34.4
GaTe (mp-542812) <0 0 1> <0 0 1> 0.098 229.1
CaF2 (mp-2741) <1 0 0> <0 0 1> 0.102 240.6
MgF2 (mp-1249) <1 0 1> <0 0 1> 0.116 343.7
GaP (mp-2490) <1 1 0> <0 0 1> 0.116 171.8
NdGaO3 (mp-3196) <1 0 1> <0 0 1> 0.117 160.4
CaF2 (mp-2741) <1 1 0> <0 0 1> 0.118 171.8
PbSe (mp-2201) <1 1 0> <0 0 1> 0.118 274.9
Mg (mp-153) <1 0 1> <0 0 1> 0.120 148.9
YVO4 (mp-19133) <1 1 0> <0 0 1> 0.125 320.8
GaTe (mp-542812) <1 0 -1> <0 0 1> 0.126 229.1
GaSb (mp-1156) <1 1 0> <0 0 1> 0.127 274.9
YAlO3 (mp-3792) <1 0 1> <1 0 0> 0.132 297.7
MgO (mp-1265) <1 1 0> <0 0 1> 0.133 229.1
ZrO2 (mp-2858) <0 1 1> <0 0 1> 0.137 274.9
CdSe (mp-2691) <1 1 0> <0 0 1> 0.139 274.9
AlN (mp-661) <1 0 1> <0 0 1> 0.146 217.7
Mg (mp-153) <1 0 0> <1 0 1> 0.151 181.9
GaSe (mp-1943) <0 0 1> <0 0 1> 0.151 148.9
BN (mp-984) <1 0 1> <0 0 1> 0.152 217.7
Cu (mp-30) <1 1 0> <0 0 1> 0.156 91.6
DyScO3 (mp-31120) <0 1 0> <0 0 1> 0.166 171.8
GaTe (mp-542812) <1 0 0> <1 0 0> 0.181 178.6
LaF3 (mp-905) <1 1 0> <0 0 1> 0.183 91.6
SiC (mp-8062) <1 1 0> <0 0 1> 0.202 137.5
C (mp-66) <1 1 0> <0 0 1> 0.205 91.6
GaN (mp-804) <1 0 0> <1 0 1> 0.210 181.9
TiO2 (mp-2657) <1 1 0> <0 0 1> 0.212 252.0
WSe2 (mp-1821) <1 0 1> <0 0 1> 0.221 252.0
Up to 50 entries displayed.
minimal coincident interface area.

Elasticity

Reference for tensor and properties:
Stiffness Tensor Cij (GPa)
108 35 28 0 -0 0
35 108 28 -0 0 0
28 28 119 0 0 0
0 -0 0 32 0 0
0 -0 0 0 32 0
0 0 0 0 -0 36
Compliance Tensor Sij (10-12Pa-1)
10.7 -3.1 -1.8 0 0 0
-3.1 10.7 -1.8 0 0 0
-1.8 -1.8 9.2 0 0 0
0 0 0 31.2 0 0
0 0 0 0 31.2 0
0 0 0 0 0 27.6
Shear Modulus GV
36 GPa
Bulk Modulus KV
57 GPa
Shear Modulus GR
36 GPa
Bulk Modulus KR
57 GPa
Shear Modulus GVRH
36 GPa
Bulk Modulus KVRH
57 GPa
Elastic Anisotropy
0.08
Poisson's Ratio
0.24

Dielectric Properties

Reference for tensor and properties: Methodology
Dielectric Tensor εij (electronic contribution)
14.27 -0.00 0.00
-0.00 14.27 0.00
0.00 0.00 6.35
Dielectric Tensor εij (total)
15.52 -0.00 -0.00
-0.00 15.52 -0.00
-0.00 -0.00 8.86
Polycrystalline dielectric constant εpoly
(electronic contribution)
11.63
Polycrystalline dielectric constant εpoly
(total)
13.30
Refractive Index n
3.41
Potentially ferroelectric?
True

Calculation Summary

Elasticity

Methodology

Structure Optimization

Run Type
GGA
Energy Cutoff
520 eV
# of K-points
28
U Values
--
Pseudopotentials
VASP PAW: K_sv Se Nb_pv
Final Energy/Atom
-5.5344 eV
Corrected Energy
-44.2751 eV
-44.2751 eV = -44.2751 eV (uncorrected energy)

Detailed input parameters and outputs for all calculations


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ICSD IDs
  • 26288

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)