Metal

Quantum mechanics

Electrical resistivity and conductivity

Catalysis

Kondo insulator

Antiferromagnetism

Strongly correlated material

Metallurgy

Materials science

Biochemistry

Acoustics

Metal–insulator transition

Lattice (music)

Non-blocking I/O

Physics

Mott insulator

Kondo effect

Doping

Superconductivity

Condensed matter physics

Chemistry

Electron

Nickel

Physical review. B./Physical review. B

We propose the parent compound of the newly discovered superconducting nickelate Nd$_{1-x}$Sr$_{x}$NiO$_{2}$ as a self-doped Mott insulator, in which the low-density Nd-$5d$ conduction electrons couple to localized Ni-3$% d_{x^{2}-y^{2}}$ electrons to form Kondo spin singlets at low temperatures. This proposal is motivated with our analyses of the reported resistivity and Hall coefficient data in the normal state, showing logarithmic temperature dependence at low temperatures. In the strong Kondo coupling limit, we derive a generalized $t$-$J$ model with both Kondo singlets and nickel holons moving through the lattice of otherwise nickel spin-1/2 background. The antiferromagnetic long-range order is therefore suppressed as observed in experiments. With Sr-doping, the number of holons on the nickel sites increases, giving rise to the superconductivity and a strange metal phase analogous to those in superconducting copper oxides.

Self-doped Mott insulator for parent compounds of nickelate superconductors