[QE-users] R: Adhesion Work

[michele de angelis]

Dear Dr. Cantele,
 thank you for your reply. I wanted to be sure of factor 2 in calculating the adhesion work and at the same time I was thinking of the same doubt you described. To be sure and remove this doubt, I will do a test even with just one interface in a vacuum and let's see if there is a difference. Thanks again!
Best Regards,

Michele De Angelis
PhD student, Dept. of Chemical Sciences and Technologies, Univesity of Rome Tor Vergata (Italy)

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Da: users <users-bounces at lists.quantum-espresso.org> per conto di Giovanni Cantele <giovanni.cantele at spin.cnr.it>
Inviato: mercoledì 22 ottobre 2025 14:32
A: Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>
Oggetto: Re: [QE-users] Adhesion Work

Hi, I would say that you should divide by two, because you have two interfaces per unit cell.

I'm just wondering what would happen for an "isolated" interface. In other words, what you are considering is actually a
"superlattice" in that the A-B sequence is periodically repeated. Consecutive replicas are separated by only 2-3 A distance.
How different would be the interface
energy you compute after adding a, let's say, 10 Ang vacuum (in this case the interface energy should be computed without dividing by 2).
In other words, I would compare the interface energy as computed from the A-B-A-B-A-B-..... superlattice [dividing by 2 as you said] with that computed
from the A-B-10 Ang-A-B-10Ang-.....structure (10Ang = vacuum) [without dividing by 2].

Giovanni
--

Prof. Giovanni Cantele
Dipartimento di Fisica "Ettore Pancini"
Universita' degli Studi di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at unina
Phone: +39 081 676910

Web page: https://sites.google.com/view/giovanni-cantele/home


Il giorno mar 21 ott 2025 alle ore 14:07 michele de angelis <michele.deangelis.01 at alumni.uniroma2.eu<mailto:michele.deangelis.01 at alumni.uniroma2.eu>> ha scritto:
Dear all,
I built a periodic supercell (no vacuum along z) with ASE, containing YBCO and STO slabs with identical terminations (and identical vaccum) on top and bottom (symmetric slabs) along (001) direction. Furthermore, the lattice parameter of the substrate (for the lattice mismatch) was imposed on the interface area. After relaxing the structure, I perform an scf calculation to determine the energy of the interface (all details on the calculation are in the attached file). I compute energies E_A (slab A, symmetric), E_B (slab B, symmetric), and E_AB (full supercell ). Now, I want to determine the adhesion work for this interface (with these terminations). If you look at the structure of the supercell, in the attached input file that dispatches the interface, you only see one interface. The cell therefore contains two equivalent interfaces (A|B and B|A) by PBC.
My question:
to report the adhesion work per unit area for a *single* interface, should I use:
W = (E_A + E_B - E_AB) / (2*A)
(i.e. divide by 2 because there are two equivalent interfaces in the cell)? or not?
Thank you in advance for your support.
 Best regards,

Michele De Angelis
PhD student, Dept. of Chemical Sciences and Technologies, Univesity of Rome Tor Vergata (Italy)

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