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Dear Chaman,
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<div class="">1. Yes. Actually, the band paths are just conventions, and try to pass through all points and lines that have some symmetry. </div>
<div class="">So, the “suggested” band paths depend a lot on the lattice (and actually also, in some cases, on the space group, if you want to cover all inequivalent lines, as we discuss in [1]).</div>
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<div class="">The band structure is not affected by the path you choose (but of course, by choosing a different path, you’ll see different bands).</div>
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<div class="">2. It’s up to you. The ones of wikipedia cover a more complete path, but in many cases the relevant features (e.g. lowest conduction band, highest valence band, …) might only appear for a given material along a subset of the lines, so you can
decide show show less paths if you know the material and what you are doing.</div>
<div class="">If you are unsure, I suggest to use our seekpath tool at <a href="https://www.materialscloud.org/work/tools/seekpath" class="">https://www.materialscloud.org/work/tools/seekpath</a> - this will also standardise the cell and check the spacegroup
symmetry, and e.g. distinguish between hP1 and hP2 (the path that you/wikipedia report is for what we call hP2; hP1 needs an additional segment K-H_2 that is for some space groups is not equivalent to K-H; our paper [1] explains more about this).</div>
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<div class="">3. I don’t know. In general they use a shorter path and this is OK. The only thing that I’m not sure about is what is the U point for them, as this is not a standard point for a hexagonal cell. I didn’t have the time to check the paper to see
if they say what U is. However, note that at U most bands do not have extrema (only one band has a minimum). </div>
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<div class="">So my guess, now that I look better at it, they might be just refolding the band structure and using the names of the letters from the cubic FCC lattice, refolded on the hexagonal lattice, and this might explain the U point (that exists in cF
lattices). </div>
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<div class="">However, to confirm this, you will need to check the refolding and try to reproduce the band structure, to know if this is the correct interpretation (or check if they explain more in the paper).</div>
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<div class="">Hope this helps,</div>
<div class="">Giovanni Pizzi</div>
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<div class="">[1] Y. Hinuma, G. Pizzi, Y. Kumagai, F. Oba, I. Tanaka, Band structure diagram paths based on crystallography, Comp. Mat. Sci. 128, 140 (2017). DOI: <a href="http://doi.org/10.1016/j.commatsci.2016.10.015" class="">10.1016/j.commatsci.2016.10.015</a></div>
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-- <br class="">
Giovanni Pizzi<br class="">
Theory and Simulation of Materials and MARVEL, EPFL<br class="">
<a href="http://people.epfl.ch/giovanni.pizzi" class="">http://people.epfl.ch/giovanni.pizzi</a><br class="">
http://nccr-marvel.ch/en/people/profile/giovanni-pizzi</div>
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<div class="">On 26 May 2020, at 17:15, Chaman Gupta <<a href="mailto:chaman@uw.edu" class="">chaman@uw.edu</a>> wrote:</div>
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<div class="gmail_default">Hey everyone,</div>
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<div class="gmail_default">I am trying to study the effect of pressure on the band structure of <u class="">'Si - simple hexagonal (Phase V)</u>', which is stable between 17 to 30 GPa (approx.)</div>
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<div class="gmail_default">Here is a paper published in Nature (<a href="https://www.nature.com/articles/s41586-020-2150-y" target="_blank" style="font-family:Arial,Helvetica,sans-serif" class="">https://www.nature.com/articles/s41586-020-2150-y</a>), which
has a figure with the band structure of Hex-Si (image is attached). The image has the following path <u class="">" A - Gamma - M - U - L ".</u></div>
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<div class="gmail_default"><a href="https://drive.google.com/file/d/1zaJSjv3RX3gy87NTuBV5AjkJysW7pdOZ/view?usp=sharing" target="_blank" class="">IMAGE 1 IS HERE</a></div>
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<div class="">When I looked for BZ1 and the path to take for a simple hexagonal structure, I came across this link (
<a href="https://en.wikipedia.org/wiki/Brillouin_zone" class="">https://en.wikipedia.org/wiki/Brillouin_zone</a>). It mentions the path to be <u class="">"Gamma - M - K - Gamma - A - L - H - A|L - M|K - H"</u></div>
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<font face="trebuchet ms, sans-serif" class=""><span class="gmail_default">My questions:</span></font></div>
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<font face="trebuchet ms, sans-serif" class=""><span class="gmail_default" style="">1. From what I understand, the path and symmetry points are dependent on the type of lattice, and highly affect the band structure. Is this statement right or wrong?</span></font></div>
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<font face="trebuchet ms, sans-serif" class=""><span class="gmail_default" style="">2. Which k-points/ High symmetry points/ BZ1/ path should I use for my band structure calculation?</span></font></div>
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<font face="trebuchet ms, sans-serif" class=""><span class="gmail_default" style="">3. Is it possible, by any chance the author of this Nature paper, might have used the wrong k-points? Or should I use what they have used?</span></font></div>
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<font face="trebuchet ms, sans-serif" class=""><span class="gmail_default" style="">Thanks for the help.</span></font></div>
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<div dir="ltr" class=""><font face="trebuchet ms, sans-serif" class="">Regards,</font>
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<div class=""><b class=""><font face="trebuchet ms, sans-serif" class="">Chaman Gupta</font></b>
<div class=""><font face="trebuchet ms, sans-serif" class="">Graduate Research Student,
<i class=""><a href="http://depts.washington.edu/nrglab/" target="_blank" class="">Novosselov Research Group</a>, UW</i><br class="">
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<div class=""><font face="trebuchet ms, sans-serif" class="">Graduate Research Student,
<i class=""><a href="https://depts.washington.edu/pzlab/wordpress/" target="_blank" class="">Pauzauskie Research Group</a>, UW</i></font></div>
<div class=""><font face="trebuchet ms, sans-serif" class="">University of Washington Seattle, <i class="">M.S. in Mechanical Engineering</i></font></div>
<div class=""><font face="trebuchet ms, sans-serif" class="">IIT Kharagpur, <i class="">B.Tech in Metallurgical and Materials Engineering</i></font></div>
<div class=""><font face="trebuchet ms, sans-serif" class=""><b class=""><a href="https://www.linkedin.com/in/professorchamangupta" target="_blank" class="">Linked In</a> |
<a href="mailto:chaman@uw.edu" target="_blank" class="">Email</a> | </b></font><span style="font-family:"trebuchet ms",sans-serif" class=""><b class="">P</b>: +1 (206) 383-3514</span></div>
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