[QE-users] Effective Mass Tensor unit-cell dependency

[Schön, Carl-Friedrich]

Dear Stefano,

that is indeed a very helpful point. Thanks a lot!


All the best,

Carl-Friedrich Schön

Von: Stefano Baroni<mailto:baroni at sissa.it>
Gesendet: Mittwoch, 22. September 2021 11:59
An: Quantum ESPRESSO users Forum<mailto:users at lists.quantum-espresso.org>
Betreff: Re: [QE-users] Effective Mass Tensor unit-cell dependency



On 22 Sep 2021, at 11:42, Schön, Carl-Friedrich <schoen at physik.rwth-aachen.de<mailto:schoen at physik.rwth-aachen.de>> wrote:

Dear Pietro,

I actually haven’t started thinking about which High Symmetry Points are comparable/identical going from one unit cell definition to the next. I was assuming that the Gamma Point (0,0,0) should be identical/equivalent no matter the representation of the unit cell.

Not a fair assumption. The states at the gamma point of an 8-atom cell are equivalent to the union of the states at the Gamma and the three X points of a 2-atom cell. It has to be so, because the number of states at each k point must be proportional to the number of atom in the unit cell (by the way, this why the so-called "density of states” is actually a DOS per unit volume …).

Hope this helps
SB

—
Stefano Baroni - Trieste —  http://stefano.baroni.me




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