[QE-users] Inaccurate bandstructure of InSb with PPs from QE PP-library

[Ritwik Das]

*Why the inclusion of '4d' electrons in the pseudopotential of In and Sb
giving erroneous InSb electronic bandstructure in Quantum Espresso?  *

Dear all,

I am struggling to obtain proper electronic band structure of InSb with
pseudopotentials (PP) available on the QE PP-library.


I was trying to obtain electronic bandstructure of InSb using Quantum
Espresso (QE). At first, I used PBE pseudopotentials (with/without
spin-orbit-coupling [SoC] and ultrasoft/PAW) available on the
QuantumEspresso website. But in any case, I didn’t get an accurate band
structure, there is no bandgap and also with SoC heavy-hole (HH) and light
hole (LH) bands are separated on GAMMA high-symmetry points
(InSb-PBE-PAW-SoC-conf1.png ). All those pseudopotentials (PP) of In and Sb
available on the QE have taken all 10 electrons of 4d orbital as their
valence electrons (for In: 4d10 5s2 5p1, for Sb: 4d10 5s2 5p3) along with
5s and 5p and rests as the core electrons.

But when I generated PBE PPs by myself without taking 4d electrons as
valence electrons (for In: 5s2 5p1, for Sb: 5s2 5p3), those PPs gave me
quite an accurate bandstructure (PBE-PAW-SOC-conf2.png).

My question is, why the inclusion of 4d electrons in the valence cell in
the PP of In and Sb (which are the default and believed to be the most
optimized configuration for PP) is not giving accurate bandstructure of
InSb?

Thank you in advance.


Regards,

Ritwik Das
---
Ritwik Das

C2N UMR CNRS 9001 - Université Paris-Saclay

Department: Physics (Nanoelectronics)
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