Phase diagram of the square-lattice t-J-V model for electron-doped cuprates

In this work, we employ density matrix renormalization group simulations and mean-field analysis to investigate the t-J-V model on square lattices, exploring the role of inter-site interactions (V) in electron-doped cuprates. We propose the t-J-V model with V~t as the minimal model to capture essential physics by presenting a phase diagram that closely aligns with experimental observations. This phase diagram demonstrates robust Néel antiferromagnetic order (AF), weak charge density wave (CDW), and absent superconductivity (SC) at light doping, the coexistence of AF and SC with increasing doping, a narrow SC region around optimal doping, and the existence of a pseudogap. Our work shows that the t-J-V model accurately captures the AF and SC phases, indicating a narrower doping range for SC and a broader range for AF, in contrast to the t-J model with opposite observations. Our systematic analysis across various doping levels reveals non-intuitive effects of V on AF and CDW and predicts an incommensurate spin density wave (iSDW) at larger doping. These findings not only align with experimental data but also enhance our understanding of electron-doped cuprates, setting the stage for future experimental and theoretical investigations into AF, SC, CDW, PG, and iSDW.