JVASP-25626_BaSi6N8O
JARVIS-ID:JVASP-25626 Functional:optB88-vdW Primitive cell Primitive cell Conventional cell Conventional cell
Chemical formula:BaSi6N8O Formation energy/atom (eV):-1.452 a 4.877 Å α:73.505 ° a 4.877 Å α:90.0 °
Space-group :Imm2, 44 Relaxed energy/atom (eV):-6.6259 b 6.83 Å β:69.084 ° b 8.174 Å β:90.0 °
Calculation type:Bulk SCF bandgap (eV):4.262 c 6.83 Å γ:69.084 ° c 9.798 Å γ:90.0 °
Crystal system:orthorhombic Point group:mm2 Density (gcm-3):3.69 Volume (3):195.29 nAtoms_prim:16 nAtoms_conv:32
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): 4.431I


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 : 4.2624 eV

Static real-parts of dielectric function in x,y,z: 4.27,4.23,4.24


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 : 5.3852 eV

Static real-parts of dielectric function in x,y,z: 3.61,3.56,3.56


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

11.67 -0.0 -0.0
-0.0 12.3 0.0
-0.0 0.0 12.64

Piezoelectric-stress-tensor (C/m2)

-0.49 -0.83 0.48 0.0 0.0 0.0
0.0 0.0 -0.0 -0.59 0.0 0.0
0.0 0.0 0.0 0.0 0.0 0.35

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): 171.47 GPa, Voigt-shear modulus (GV): 106.26 GPa

Reuss-bulk modulus (KR): 168.04 GPa, Reuss-shear modulus (GR): 98.18 GPa

Poisson's ratio: 0.25, Elastic anisotropy parameter: 0.43

Clarke's lower limit of thermal conductivity (W/(m.K)): 1.89

Cahill's lower limit of thermal conductivity (W/(m.K)): 2.06

Elastic tensor
342.1 73.3 75.1 -0.0 0.0 -0.0
73.3 274.5 123.3 0.0 0.0 -0.0
75.1 123.3 383.2 0.0 -0.0 -0.0
-0.0 0.0 0.0 132.0 0.0 0.0
0.0 -0.0 -0.0 0.0 88.8 -0.0
0.0 -0.0 0.0 0.0 -0.0 67.8

Phonon mode (cm-1)
-0.09
-0.09
-0.04
48.59
68.62
73.14
74.16
74.49
75.34
79.27
111.61
175.0
187.65
194.79
217.16
229.77
235.99
237.39
237.63
255.73
266.36
270.96
282.2
300.07
311.32
314.39
325.49
329.34
333.49
338.48
344.57
370.32
373.59
382.83
385.32
397.74
405.4
414.6
420.65
428.65
438.86
440.29
446.15
468.68
474.15
476.21
479.28
481.77
499.19
510.98
513.45
515.64
537.58
574.0
599.7
617.01
620.39
622.98
644.81
657.28
660.73
670.09
684.94
704.0
745.77
745.78
802.59
809.28
813.19
822.66
824.75
830.17
835.53
852.3
859.53
860.91
880.1
884.35
887.34
901.08
901.66
924.16
929.2
944.63
945.87
946.5
954.82
972.26
1003.45
1049.67
1062.17
1069.33
1076.09
1111.81
1120.17
1190.91

Point group

point_group_type: mm2

Visualize Phonons here
Phonon mode (cm-1) Representation
-0.09
-0.0944298667
-0.04
-0.042156243
74.16
74.1623712141
74.49
74.4898664397
79.27
79.2662466473
187.65
187.646436012
237.39
237.387176048
255.73
255.730163361
266.36
266.360507607
282.2
282.197872226
314.39
314.391634377
325.49
325.48819704
329.34
329.342414678
338.48
338.481967537
344.57
344.574953117
373.59
373.593841153
382.83
382.832383052
385.32
385.315847314
420.65
420.652883783
428.65
428.652889923
446.15
446.153636354
468.68
468.682941576
481.77
481.772027105
499.19
499.191913882
513.45
513.448659006
574.0
574.000852426
620.39
620.390116278
622.98
622.980274394
657.28
657.281776082
660.73
660.725333331
670.09
670.090175011
745.78
745.781630593
809.28
809.27506885
824.75
824.745320593
830.17
830.173875305
835.53
835.530875327
852.3
852.295881812
887.34
887.33937892
901.08
901.080957789
901.66
901.660336863
944.63
944.629411867
946.5
946.495033485
954.82
954.823512083
972.26
972.260896775
1069.33
1069.33432007
1111.81
1111.81104629
1120.17
1120.16923415

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)

0.97 0.14 0.0
0.14 1.1 -0.36
0.0 -0.36 0.96

Hole mass tensor (me unit)

10.07 0.1 3.04
0.1 2.23 -0.27
3.04 -0.27 3.29

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 -314.51 -309.86 -288.16
n-PowerFactor 1361.55 2356.33 2466.41
n-Conductivity 13765.02 25688.07 28377.79
n-ZT 0.7 1.11 1.21
p-Seebeck 384.95 409.68 413.09
p-PowerFactor 373.57 1471.25 1594.7
p-Conductivity 2189.2 9501.65 9928.34
p-ZT 0.22 0.84 0.9

See also

Links to other databases or papers are provided below


mp-557414

ICSD-ID: 415272

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MP link
mp-557414

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