Effect of pressure on the electronic structure of antiferromagnetic and paramagnetic YNiO 3 : the role of disproportionation.

The dependence of electronic properties of quantum materials on external controls ( e.g. , pressure and temperature) is one of the fundamentals of neuromorphic computing, sensors, etc. Until recently, it has been believed that the theoretical description of such compounds cannot be accomplished using "traditional" density functional theory, and more advanced methods like dynamic mean-field theory should be utilized instead. Focusing here on the example of long-range ordered antiferromagnetic and paramagnetic YNiO 3 phases, we show the interplay between spin and structural motifs under pressure and their impact on electronic properties. We successfully describe the insulating nature of both YNiO 3 phases and the role of symmetry-breaking motifs in the band gap opening. Moreover, by analyzing the pressure-dependent distribution of local motifs, we show that external pressure can significantly reduce the band gap energy of both phases, originating from the reduction of structural and magnetic disproportionation - change in the distribution of local motifs. These results thus demonstrate that some of the experimental observations in quantum materials ( e.g. , YNiO 3 compounds) can be fully understood without accounting for dynamic correlation.