Polaron Modulated Electronic Structures of Doped La₂CuO₄ by Self-Interaction Corrected Density Funcional Theory Approach

Single-particle ab-initio approaches, e.g., density functional theory (DFT) with standard exchange-correlation functionals, is notorious for its poor treatment of the electronic structures of cuprate superconductors, not to mention their properties upon doping. Here, taking La₂CuO₄ (LCO) as an exemplar, with both T and T’ phase, we show that self-interaction corrected DFT accurately produces the experimentally observed insulator to metal transition, as a function of hole and electron doping concentration, respectively. Based on our calculations, doped carriers form localized polarons under low doping concentration dissolving into extended states upon high doping concentration, thus making the system conducting. The correct description of LCO provides us a practical route to the doping problems of strong correlated materials within Kohn-Sham DFT framework, which is capable to treat a larger supercell than the methods beyond DFT.