2025/01/15 by Wang, Yuxin, Chen, Ziyan, Zhang, Yi +2 · 1 citation
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2501.08536
The oxygen content plays a pivotal role in determining the electronic and superconducting properties of the recently discovered La3Ni2O7-δ superconductors. In this work, we investigate the impact of oxygen vacancies on the insulating behavior of La3Ni2O7-δ across the doping range δ= 0 to 0.5. At δ= 0.5, we construct a bilayer two-orbital Hubbard model to describe the system. Using dynamical mean-field theory, we demonstrate that the model captures the characteristics of a bilayer Mott insulator. To explore the effects of disorder within the range δ= 0 to 0.5, we treat the system as a mixture of metallic and Mott insulating phases. By applying the dynamical cluster approximation and the typical medium dynamical cluster approximation, we identify an Anderson localization transition at a critical doping of δ∼ 0.2 through the geometric average of the local density of states. This Anderson localization transition is the key reason for the suppression of superconductivity in La3Ni2O7-δ. These results provide a quantitative explanation of recent experimental observations and highlight the critical influence of oxygen content on the physical properties of La3Ni2O7-δ.