First-principles study of pressure effects on the physical, chemical and magnetic properties of LaCrGe ₃

We explore the pressure induced magnetic transition in LaCrGe₃ using density functional theory, revealing a complex interplay between its electronic structure and magnetism. While the first-principles calculations reproduce experimental structural parameters, they overestimate the critical pressure for the transition to a nonmagnetic state. Discrepancies between theoretical and experimental transition pressures, coupled with persistent magnetic moments at higher pressures, suggest the necessity of accounting for spin fluctuations. Employing fixed spin moment calculations and Ginzburg-Landau expansion, we demonstrate the crucial role of spin fluctuations in accurately describing the magnetic phase transition. This methodology yields a transition pressure closer to the experimental value. This work underscores the limitations of static mean-field approaches for fragile magnets such as LaCrGe₃, emphasizing the importance of incorporating spin fluctuations for understanding the magnetic behavior of LaCrGe₃ under pressure.