First-principles and Monte Carlo simulations of high-entropy MXenes

Abstract

In this work, we developed a computational framework that integrates first-principles density functional theory (DFT) calculations with Monte Carlo (MC) algorithm to search for the most stable configuration of high-entropy (HE) MXenes. This framework can predict the minimum energy configurations of HE MXenes with interlayer segregation. For instance, DFT/MC simulation indicates that (Ti0.5Cr0.5)4C3 MXenes exhibit interlayer segregation, where Cr atoms are favorable to segregate into the outermost top and bottom layers, forming out-of-plane MXene (o-MXenes). Such an o-MXene structure was also found in (Nb0.5Mo0.5)4C3, (Cr0.5Mo0.5)4C3, and (Ti0.33Cr0.33Mo0.34)4C3 MXenes, which is in good agreement with prior studies. The classical molecular dynamics (MD)/MC simulations using machine learning interatomic potentials further validate the interlayer segregation-induced o-MXene observed in the DFT/MC simulations. This DFT/MC framework can be easily extended to predict the stable phases for other material systems, suggesting its broad applicability and impact.