Stochastic density functional theory (SDFT) [1,2] and the related mixed stochastic-deterministic density functional theory [3], based on the plane-wave basis set, have been implemented in the first-principles electronic structure software ABACUS [4]. In the traditional finite-temperature Kohn-Sham density functional theory (KSDFT), a well-known orbitals wall limits the first-principles molecular dynamics method to be used at extremely high temperatures. Combining with the Born-Oppenheimer molecular dynamics (BOMD) method, we apply the SDFT method to study systems with temperatures ranging from a few tens of eV to 1000 eV. Additionally, we train machine-learning-based interatomic models [5,6] from the SDFT data and used them in BOMD simulations. As a result, the structural properties, dynamic properties, and transport coefficients of warm dense matter are computed with longer trajectory time and larger system sizes. The abovementioned methods offer a new approach with first-principles accuracy to tackle properties of warm dense matter.
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[2] Y. Cytter, E. Rabani, D. Neuhauser, and R. Baer, Stochastic Density Functional Theory at Finite Temperatures, Phys. Rev. B 97, 115207 (2018).
[3] A. J. White, L. A. Collins, K. Nichols, and S. X. Hu, Mixed Stochastic-Deterministic Time-Dependent Density Functional Theory: Application to Stopping Power of Warm Dense Carbon, J. Phys. Condens. Matter 34, 174001 (2022).
[4] Q. Liu and M. Chen, Plane-Wave-Based Stochastic-Deterministic Density Functional Theory for Extended Systems, Phys. Rev. B 106, 125132 (2022).
[5] L. Zhang, J. Han, H. Wang, R. Car, and W. E, Deep Potential Molecular Dynamics: A Scalable Model with the Accuracy of Quantum Mechanics, Phys. Rev. Lett. 120, 143001 (2018).
[6] H. Wang, L. Zhang, J. Han, and W. E, DeePMD-Kit: A Deep Learning Package for Many-Body Potential Energy Representation and Molecular Dynamics, Comput. Phys. Commun. 228, 178 (2018).