GAP interatomic potential for PtAu:H nanoparticle simulation

Gaussian approximation potential (GAP) [1] for the platinum-gold-hydrogen system. It can be safely used to generate PtAu nanoparticles throughout the whole composition range and to hydrogenate them (add adsorbed H on the surface). For any other system, the accuracy and stability of the potential should be specifically tested (e.g., against reference DFT calculations). It has been fitted with gap_fit [2] by generating a new database of atomic structures containing:

1. bulk PtAu structures, including 3x3x3 supercells with substitutional alloying as determined by cluster-expansion configurations generated by the CASM code [10];
2. PtAu surface slabs, with random alloying and H adsorption at different coverages;
3. iteratively generated PtAu clusters (nanoparticles), following a similar approach as in Ref. [3], and adding H coverage to those.

The calculations were carried out at the PBE level of theory [4] using the VASP code [5,6]. This potential uses 2-body (distance_2b) and SOAP-type descriptors (soap_turbo) [7,8]. The files can be used both with QUIP/GAP (compiled with the soap_turbo libraries) and TurboGAP [9]. The reference publication for this potential will be added in time (e.g., when a preprint is a valable, and then updated when a journal publication is available).

Financial support from the Research Council of Finland and computational resources from CSC (the Finnish IT Center for Science) and Aalto University's Science-IT project are gratefully acknowledged.

References

1. A.P. Bartók, M.C. Payne, R. Kondor, and G. Csányi. Phys. Rev. Lett. 104, 136403 (2010).
2. S. Klawohn, J.P. Darby, J.R. Kermode, G. Csányi, M.A. Caro, and A.P. Bartók. J. Chem. Phys. 159, 174108 (2023).
3. J. Kloppenburg, L.B. Pártay, H. Jónsson, and M.A. Caro. J. Chem. Phys. 158, 134704 (2023).
4. J.P. Perdew, K. Burke and M. Ernzerhof. Phys. Rev. Lett. 77, 3865 (1996).
5. VASP: http://vasp.at
6. G. Kresse and J. Furthmüller. Phys. Rev. B 54, 11169 (1996).
7. A.P. Bartók, R. Kondor, and G. Csányi. Phys. Rev. B 87, 184115 (2013).
8. M.A. Caro. Phys. Rev. B 100, 024112 (2019).
9. TurboGAP: http://turbogap.fi
10. https://prisms-center.github.io/CASMcode_docs