Electronic Structure and molecular dynamics study of the multiferroic hexagonal LuMnO ₃ material

This study examines the time evolution of the hexagonal LuMnO 3 in its ferromagnetic configuration using static density functional theory (DFT) and finite-temperature molecular dynamics (MD). Static DFT results demonstrate MnO 5 trigonal bipyramids with short equatorial and elongated apical Mn-O bonds, and a stable Lu-O coordination, which underpin the ferroelectric lattice distortion and electronic polarization. The band structure and Density of States reveal a ferromagnetic ground state supported by significant Mn-O hybridization. To investigate dynamical stability, Verlet, Nosé-Hoover, and Parrinello-Rahman dynamics were used in time-integrated MD simulations under various ensembles (NVE, NVT, and NPE). The study found that temperature fluctuations do not affect the fundamental lattice distortions, such as tilting of MnO 5 bipyramids and Lu-O bonding asymmetry. This preserves conditions conducive for multiferroicity. The research emphasizes the significance of ensemble and thermostat/barostat parameter selection in capturing true finite-temperature behavior. Correlating static and dynamic findings reveals that the durability of ferroelectric polarization is due to Mn-O bond strength, whereas Lu-O coordination stabilizes the multilayer hexagonal framework. This study bridges the gap between static first-principles predictions and finite-temperature events, revealing the robustness of multiferroicity in LuMnO 3 . Our findings demonstrate the value of combined DFT-MD techniques for understanding structure-property relationships in complicated oxides, paving the way for further research into phonons, spin-lattice coupling, and experimental validation under different conditions.