**Question about unit of electric field calculation** |
- Date: 2024/05/03 09:55
- Name:
**CHOI**
<gustjr0406@inu.ac.kr>
- Hello, my name is CHOI and I'm doing research about 2D materials' electrical properties.
I was calculating band structure of 2D 1T' MoS2 with vacuum area along z-axis by applying external electric field.
It is known that 2D 1T' MoS2 has non zero bulk gap when there is no external field, but bulk gap decreases if there external e-field has applied along the direction which is perpendicular to the 2D material. (along z-axis in this case.) It is also known that bulk gap is zero (crossing) at some amount of e-field (critical e-field) and then bulk gap increases again.
What I want to know with this calculation is the intensity of critical e-field. For reference, I found a paper which did same calculation in VASP, and that critical e-field was 0.142 V/Ang. The value I got from openMX is 1.2 V/Ang which is almost ten times bigger than the result from VASP.
The paper provided information about unit vectors and atom positions, so I used same atomic structure with paper. And I got band structure which is almost same with the one calculated by VASP. So I think the calculation itself is not that wrong, but the unit of e-field in openMX manual could be written wrong by mistake.
In openMX manual, it says the unit of e-field is GV/m = 10^9 V/m. Can I trust that unit 100%? or is it possible to think it was written wrong?
These are my input settings for scf calculation.
33 scf.XcType GGA-PBE 34 scf.SpinPolarization nc 35 scf.SpinOrbit.Coupling on 36 scf.ElectronicTemperature 300.0 37 scf.energycutoff 220.0 38 scf.maxIter 100 39 scf.EigenvalueSolver band 40 scf.Kgrid 9 9 1 41 scf.Mixing.Type rmm-diisk 42 scf.Init.Mixing.Weight 0.05 43 scf.Min.Mixing.Weight 0.01 44 scf.Max.Mixing.Weight 0.30 45 scf.Mixing.History 25 46 scf.Mixing.StartPulay 15 47 scf.criterion 1.0e-7 48 scf.Electric.Field 0.0 0.0 1.0 #GV/m, 10GV/m = V/Ang
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