Quary regarding band structure and bulk modulus calculation of Te (ID: mp-19)

Materials Project
#1

Sir/Madam,

I am trying to reproduce the electronic structure and elastic properties of Bulk-Te given in https://materialsproject.org/materials/mp-19/ . My queries are the following:

  1. There are two values of band gap reported for bulk-Te: a) 0.575 eV written in material details panel, b) 0.184 eV from band structure along H(0.33, 0.33, 0.45) point of BZ.

I have calculated the band structure (non-magnetic) of the same taking same kpath with PBE-GGA and DFT-TS scheme and got band gap 0.124 eV. How can I reproduce the reported values?

  1. There is a energy-vs-volume curve reported. How can I construct the strained structure for this?

I am interested to study the anisotropy of bulk-Te structure. How can I calculate bulk modulus along specific direction?

Please give your suggestions.

Thank you in advance. With regards,
Shiladitya

#2

Hi @Shiladitya1995, welcome!

I will defer the question about band gap to a colleague. For this:

I am interested to study the anisotropy of bulk-Te structure. How can I calculate bulk modulus along specific direction?

Note we have predicted the full elastic tensor for this material, see https://materialsproject.org/materials/mp-19/#elastic-tensor This tensor contains information on stress-strain relationships along specific directions.

There is a energy-vs-volume curve reported. How can I construct the strained structure for this?

For energy-vs-volume curves, these were calculated using an Equations of State workflow and the atomate code. If you just want to strain a crystal structure to have a specific volume however, this is readily done using pymatgen e.g. the function Structure.scale_lattice.

Hope this helps,

Matt

1 Like
#3

Hi @Shiladitya1995,

There are two values of band gap reported for bulk-Te: a) 0.575 eV written in material details panel, b) 0.184 eV from band structure along H(0.33, 0.33, 0.45) point of BZ.

This discrepancy is most likely due to a bug in how we parse band gaps from different calculations. The second value from the band structure is definitely the one we should be choosing for the website. We should be rolling out an update fairly soon that will fix this.

I have calculated the band structure (non-magnetic) of the same taking same kpath with PBE-GGA and DFT-TS scheme and got band gap 0.124 eV. How can I reproduce the reported values?

Is your band gap at the same k-point? This looks like a small difference to me, and this question is hard to answer without looking at your specific calculation parameters. You should be able to reproduce the data using the line-mode band structure workflow within atomate with the default parameters.

2 Likes
#4

Sir,

Thank you for your reply and informations. The code “atomate” and “pymatgen” seems very interesting and useful to me.

Can I install the pymatgen code in Laptop?

I want to reproduce the elastic tensor for Bulk-Te manually so that I can learn to do it for other systems. For that I need to generate the structures putting strain along specific directions. You have already mentioned the function Structure.scale_lattice of pymatgen. Can you help me or provide some reference of examples to use such function to generate strained structures.

Thanks again and regards,
Shiladitya.

#5

Sir,

Thank you for your reply and informations.

Yes, I have got the band gap at same k-point H(0.33, 0.33, 0.45). I notice that density of states of bulk-Te is plotted for up and down spin channels. So is it spin polarised calculation which generate the band structure?

The code “atomate” seems very interesting and useful to me. But I think “atomate” can only be installed in supercomputers? I think it will be bit difficult for me to install it.

Thanks again and regards,
Shiladitya.