JVASP-9401_NaGaO2
JARVIS-ID:JVASP-9401 Functional:optB88-vdW Primitive cell Primitive cell Conventional cell Conventional cell
Chemical formula:NaGaO2 Formation energy/atom (eV):-2.014 a 5.342 Å α:90.0 ° a 5.342 Å α:90.0 °
Space-group :Pna2_1, 33 Relaxed energy/atom (eV):-3.2368 b 5.57 Å β:90.0 ° b 5.57 Å β:90.0 °
Calculation type:Bulk SCF bandgap (eV):3.001 c 7.236 Å γ:90.0 ° c 7.236 Å γ:90.0 °
Crystal system:orthorhombic Point group:mm2 Density (gcm-3):3.85 Volume (3):215.29 nAtoms_prim:16 nAtoms_conv:16
Download input files

Convergence [Reference]

Calculations are done using VASP software [Source-code]. Convergence on KPOINTS [Source-code] and ENCUT [Source-code] is done with respect to total energy of the system within 0.001 eV tolerance. Please note convergence on KPOINTS and ENCUT is generally done for target properties, but here we assume energy-convergence with 0.001 eV should be sufficient for other properties also. The points on the curves are obtained with single-point calculation (number of ionic steps, NSW=1 ). However, for very accurate calculations, NSW>1 might be needed.


Structural analysis [Reference]

The following shows the X-ray diffraction (XRD)[Source-code] pattern and the Radial distribution function (RDF) plots [Source-code]. XRD peaks should be comparable to experiments for bulk structures. Relative intensities may differ. For mono- and multi-layer structures , we take the z-dimension during DFT calculation for XRD calculations, which may differ from the experimental set-up.


Electronic structure [Reference]

The following shows the electronic density of states and bandstructure [Source-code]. DFT is generally predicted to underestimate bandgap of materials. Accurate band-gaps are obtained with higher level methods (with high computational requirement) such as HSE, GW , which are under progress. If available, MBJ data should be comparable to experiments also. Total DOS, Orbital DOS and Element dos [Source-code] buttons are provided for density of states options. Energy is rescaled to make Fermi-energy zero. In the bandstructure plot [Source-code], spin up is shown with blue lines while spin down are shown with red lines. Non-degenerate spin-up and spin-down states (if applicable) would imply a net orbital magnetic moment in the system. Fermi-occupation tolerance for bandgap calculation is chosen as 0.001.

High-symmetry kpoints based bandgap (eV): 3.0D


Electrostatic potential [Reference]

The following plot shows the plane averaged electrostatic potential (ionic+Hartree) along x, y and z-directions. The red line shows the Fermi-energy while the green line shows the maximum value of the electrostatic potential. For slab structures (with vacuum along z-direction), the difference in these two values can be used to calculate work-function of the material.


Optoelectronic properties Semi-local [Reference]

Incident photon energy dependence of optical is shown below [Source-code]. Only interband optical transitions are taken into account.Please note the underestimatation of band-gap problem with DFT will reflect in the spectra as well. For very accurate optical properties GW/BSE calculation would be needed, which is yet to be done because of their very high computational cost. Optical properties for mono-/multi-layer materials were rescaled with the actual thickness to simulation z-box ratio. Absorption coeffiecient is in cm-1 unit. Also, ionic contributions were neglected.

Dense k-mesh based bandgap is : 3.0014 eV

Static real-parts of dielectric function in x,y,z: 3.17,3.21,3.19


Optoelectronic properties METAGGA-MBJ [Reference]

Single point DFT calculation was carried out with meta-gga MBJ potential [Source-code]. This should give reasonable bandgap, and optical properties assuming the calculation was properly converged. Incident photon energy dependence of optical is shown below. Only interband optical transitions are taken into account. Also, ionic contributions were neglected.

MBJ bandgap is : 5.4202 eV

Static real-parts of dielectric function in x,y,z: 1.42,3.03,1.58


DFPT: IR-intensity, Piezoelecric and Dielectric tensors [Reference]

Calculations are done using density functional perturbation theory (DFPT) method for non-metallic systems for conventional cell and at Gamma-point in phonon BZ.

Static dielecric-tensor

7.01 0.0 0.0
0.0 6.81 0.0
0.0 0.0 5.62

Piezoelectric-stress-tensor (C/m2)

-0.93 0.28 0.52 0.0 0.0 0.0
-0.0 0.0 0.0 0.3 0.0 0.0
-0.0 0.0 -0.0 0.0 0.0 0.27

Finite-difference: elastic tensor and derived phonon properties [Reference]

Elastic tensor calculated for the conventional cell of the system with finite-difference method [Source-code]. For bulk structures, elastic constants are given in GPa unit . For layered materials, the elastic constants are rescaled with respect to vacuum padding (see the input files) and the units for elastic coefficients are in N/m . Phonons obtained [Source-code] from this calculation are also shown.

WARNING: Please note we provide finite-size cell phonons only. At least 1.2 nm x1.2 nm x1.2 nm size cell or more is generally needed for obtaining reliable phonon spectrum, but we take conventional cell of the structure only. For systems having primitive-cell phonon representation tables, I denotes infrared activity and R denotes Raman active modes (where applicabale). Selection of particular q-point mesh can give rise to unphysical negative modes in phonon density of states and phonon bandstructre. The minimum thermal conductivity was calculated using elastic tensor information following Clarke and Cahill formalism.

Voigt-bulk modulus (KV): 81.71 GPa, Voigt-shear modulus (GV): 34.19 GPa

Reuss-bulk modulus (KR): 75.77 GPa, Reuss-shear modulus (GR): 28.86 GPa

Poisson's ratio: 0.32, Elastic anisotropy parameter: 1.0

Clarke's lower limit of thermal conductivity (W/(m.K)): 0.99

Cahill's lower limit of thermal conductivity (W/(m.K)): 1.11

Elastic tensor
114.6 37.7 68.6 -0.0 -0.0 -0.0
37.7 113.1 82.2 0.0 0.0 -0.0
68.6 82.2 130.7 -0.0 0.0 0.0
-0.0 0.0 -0.0 23.3 -0.0 -0.0
-0.0 0.0 -0.0 -0.0 46.1 -0.0
-0.0 -0.0 0.0 -0.0 -0.0 44.9

Phonon mode (cm-1)
-0.09
-0.04
-0.02
104.08
106.95
115.65
140.71
146.34
158.14
161.48
161.61
190.53
191.92
199.35
200.46
202.45
214.24
220.78
224.82
241.22
256.03
260.54
267.56
274.28
278.24
283.34
290.07
290.91
292.93
319.91
323.91
340.84
424.32
427.06
439.07
454.74
475.67
481.06
500.78
510.43
618.4
626.84
636.4
644.86
651.81
700.07
711.38
716.57

Point group

point_group_type: mm2

Visualize Phonons here
Phonon mode (cm-1) Representation
-0.09
-0.08792669
-0.04
-0.0382520112
-0.02
-0.0189837086
104.08
104.07634413
106.95
106.94521579
115.65
115.648999161
140.71
140.712550463
146.34
146.341288262
158.14
158.142966779
161.48
161.476299651
161.61
161.608435333
190.53
190.527024459
191.92
191.922358024
199.35
199.350748246
200.46
200.458110148
202.45
202.450644291
214.24
214.236995845
220.78
220.781067213
224.82
224.82280317
241.22
241.219552354
256.03
256.025094189
260.54
260.543424343
267.56
267.561011325
274.28
274.277653294
278.24
278.238792749
283.34
283.34324283
290.07
290.074961519
290.91
290.913047461
292.93
292.928367679
319.91
319.907937336
323.91
323.906129925
340.84
340.839074304
424.32
424.315316956
427.06
427.063142223
439.07
439.069139728
454.74
454.741812883
475.67
475.674178776
481.06
481.061109515
500.78
500.783173949
510.43
510.427628775
618.4
618.403226704
626.84
626.844957043
636.4
636.402466729
644.86
644.860972065
651.81
651.80829222
700.07
700.066622887
711.38
711.379749774
716.57
716.571585542

Thermoelectric properties [Reference]

Thermoelectric properties are calculated using BoltzTrap code [Source-code]. Electron and hole mass tensors (useful for semiconductors and insulators mainly)are given at 300 K [Source-code]. Following plots show the Seebeck coefficient and ZT factor (eigenvalues of the tensor shown) at 300 K along three different crystallographic directions. Seebeck coefficient and ZT plots can be compared for three different temperatures available through the buttons given below. Generally very high Kpoints are needed for obtaining thermoelectric properties. We assume the Kpoints obtained from above convergence were sufficient [Source-code].

WARNING: Constant relaxation time approximation (10-14 s) and only electronic contribution to thermal conductivity were utilized for calculating ZT.

Electron mass tensor (me unit)

0.41 0.0 0.0
0.0 0.51 -0.0
0.0 -0.0 0.31

Hole mass tensor (me unit)

4.76 -0.0 -0.0
-0.0 11.9 0.0
-0.0 0.0 7.37

n-& p-type Seebeck coeff. (µV/K), power-factor (µW/(mK2)), conductivity (1/(*m)), zT (assuming lattice part of thermal conductivity as 1 W/(mK)) at 600K and 1020 cm-3 doping. For mono/multi-layer materials consider Seebeck-coeff only.)

Property xx yy zz
n-Seebeck -110.92 -104.53 -97.19
n-PowerFactor 706.79 709.45 756.18
n-Conductivity 57662.05 64685.32 80046.32
n-ZT 0.23 0.23 0.24
p-Seebeck 435.52 441.38 479.96
p-PowerFactor 234.02 267.1 438.33
p-Conductivity 1159.5 1233.8 2249.96
p-ZT 0.14 0.16 0.26

Magnetic moment [Reference]

The orbital magnetic moment was obtained after SCF run. This is not a DFT+U calculation, hence the data could be used to predict zero or non-zero magnetic moment nature of the material only.

Total magnetic moment: -0.0 μB

Magnetic moment per atom: -0.0 μB

Magnetization
Elementsspdtot
Na0.00.00.00.0
Na-0.0-0.00.0-0.0
Na-0.0-0.00.0-0.0
Na0.00.00.00.0
Ga0.0-0.00.00.0
Ga-0.0-0.00.0-0.0
Ga-0.00.00.0-0.0
Ga0.0-0.00.00.0
O0.00.00.00.0
O-0.0-0.00.0-0.0
O-0.00.00.0-0.0
O0.0-0.00.00.0
O-0.0-0.00.0-0.0
O-0.0-0.00.0-0.0
O0.0-0.00.00.0
O0.0-0.00.00.0

See also

Links to other databases or papers are provided below


mp-3338

ICSD-ID: 4416

AFLOW link

MP link
mp-3338

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