Explorations and discoveries of complex materials with novel properties using advanced density functional theory

Complex materials with novel properties, such as heavy-Fermion compounds and high-Tc superconductors, have drawn intensive interest not only for their potential applications in material and quantum information science but also for their scientific significance. However, accurately modeling these materials has been a challenge. Therefore, the development of advanced computational methods plays a critical role in materials science, chemistry, and condensed matter physics by providing valuable insights into the underlying physics and properties of novel materials. In the first part of this discussion, I will show the importance of the strongly-constrained and appropriately-normed (SCAN) functional with symmetry breaking in advancing the theoretical treatment of highly correlated materials. Specifically, I will share our insights on the puzzles of the heavy-fermion compound SmB₆, including its highly debated quantum oscillations. Additionally, I will present our in-depth understanding of the electronic correlations in the newly discovered superconductor LaNiO₂. The charge density wave vectors predicted by our calculations are in good agreement with experimental observations, indicating the importance of electron-phonon coupling in this material.

In the second part, I will show how allowing for non-integer nuclear charges expands the space of computationally tractable electron systems that host competing electronic states. The simple 2- 2-electron H2 molecule exemplifies this by showing the competition between charge transfer and strong correlations. Additionally, the emergence of competing electronic states in doped quasi-1D cuprate chains were demonstrated using this approach. Our findings are showing how non-integer nuclear charges can open a window for first-principles calculations of difficult many-electron phenomena.