First-Principles Linear Response Calculation of Hubbard U for Terbium under High Pressure

Density functional theory (DFT) with standard LDA or GGA functionals is often insufficient to describe strongly correlated materials. The inclusion of Hubbard U for on-site electron interaction can substantially improve the accuracy in modeling their electronic and magnetic properties. The integration of the Hubbard U within DFT (DFT+U) has emerged as an efficient and robust ab initio approach for correlated electron systems. Here, we use DFT+U to study Terbium (Tb) in the pressure range 0-60 GPa. With the crystal structures informed by experiments, we systematically compute the U values of Tb as a function of pressure using linear response approach. The experimental crystal structure and linear response U further enable us to examine different low-temperature magnetic phases of Tb. Our study also provides the necessary inputs for other advanced quantum many-body techniques to model rare-earth metals for their potential applications in extreme pressure conditions.