[QE-users] SPIN ORBIT COUPLING & LDAU IN QUANTUM ESPRESSO

[Iurii TIMROV]

Dear QE user,


Please sign your posts with your name and affiliation.


Starting from QE7.1 there is a new input syntax in DFT+U and its extensions. Please check q-e/Doc/Hubbard_input.pdf. I provide answers below for QE7.1.


> Does quantum espresso use by default the Dudarev approximation even when spin orbit is switched ON?


No. It uses the Lichtenstein formulation in this case (noncolin=.true. and lspinorb=.true.). All this is handled by the routine Modules/read_cards.f90 -> card_hubbard.


> Does any of you have an idea on how to switch to the Lichtenstein formulation in the input file?


Two ways:

1) use noncolin=.true.

2) set some value of J (it can be very small)


Note that in the future official releases of QE there will be an extension of the Dudarev formulation to the nocollinear case (there is one person in our group who already implemented this in the private version of QE). BTW, it will be presented during the APS March Meeting 2023.


> Alternatively, could you share the paper that describes LDAU+U+SOC implementation in Quantum ESPRESSO?


There are some references in q-e/Doc/Hubbard_input.pdf. I am not sure though that the SOC implementation is discussed there. You can contact the person who implemented this (if I am not wrong): https://iramis.cea.fr/Pisp/alexander.smogunov/


> Which version of the code fully supports LDA+U+SOC?


This was implemented long time ago in the Lichtenstein formulation in QE. So take any version of QE of last ~15 years and try it out. I recommend to use the latest version.


HTH


Greetings,

Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Sifuna James <sifunajames at gmail.com>
Sent: Friday, October 21, 2022 11:30:58 AM
To: users at lists.quantum-espresso.org
Subject: [QE-users] SPIN ORBIT COUPLING & LDAU IN QUANTUM ESPRESSO

Greetings to you!

- Does quantum espresso use by default the Dudarev approximation even when spin orbit is switched ON?

I guess that in the Dudarev approach, you are not discriminating between the correlated orbitals with different "m" as you should do if the "spin see the lattice " and this is not so good.

- Does any of you have an idea on how to switch to the Lichtenstein approach in the input file?

- Alternatively, could you share the paper that describes LDAU+U+SOC implementation in Quantum ESPRESSO?

- Which version of the code fully supports LDA+U+SOC?
J.


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