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We investigate charge distribution in the recently discovered high-$T_c$ superconductors, layered nickelates. With increasing value of charge-transfer energy we observe the expected crossover from the cuprate to the local triplet regime upon hole doping. We find that the $d-p$ Coulomb interaction $U_{dp}$ plays a role and makes Zhang-Rice singlets less favorable, while the amplitude of local triplets is enhanced. By investigating the effective two-band model with orbitals of $x^2-y^2$ and $s$ symmetries we show that antiferromagnetic interactions dominate for electron doping. The screened interactions for the $s$ band suggest the importance of rare-earth atoms in superconducting nickelates.
The recent discovery of superconductivity in hole-doped NdNiO$_2$ thin films has captivated the condensed matter physics community. Such compounds with a formal Ni$^+$ valence have been theoretically proposed as possible analogues of the cuprates, an
To understand the superconductivity recently discovered in Nd$_{0.8}$Sr$_{0.2}$NiO$_2$, we carried out LDA+DMFT (local density approximation plus dynamical mean-field theory) and magnetic force response calculations. The on-site correlation in Ni-$3d
We have performed an angle-resolved photoemission spectroscopy study of La$_{0.6}$Sr$_{0.4}$FeO$_3$ using {it in situ} prepared thin films and determined its band structure. The experimental band dispersions could be well explained by an empirical ba
We report a systematic magnetotransport study of superconducting infinite-layer nickelate thin films Nd$_{1-x}$Sr$_x$NiO$_2$ with $0.15 leq x leq 0.225$. By suppressing superconductivity with out-of-plane magnetic fields up to 37.5 T, we find that th
By combining neutron scattering and magnetization measurements down to 80 mK, we determine the $(H,T)$ phase diagram of the Nd$_2$(Zr$_{1-x}$Ti$_x$)$_2$O$_7$ pyrochlore magnet compounds. In those samples, Zr is partially substituted by Ti, hence tuni