Magnetic order-disorder transitions on a one-third-depleted square lattice

Abstract

Quantum Monte Carlo simulations are used to study the magnetic and transport properties of the Hubbard Model, and its strong coupling Heisenberg limit, on a one-third depleted square lattice. This is the geometry occupied, after charge ordering, by the spin-1 2 Ni1+ atoms in a single layer of the nickelate materials La4Ni3O8 and (predicted) La3Ni2O6. Our model is also a description of strained graphene, where a honeycomb lattice has bond strengths which are inequivalent. For the Heisenberg case, we determine the location of the quantum critical point (QCP) where there is an onset of long range antiferromagnetic order (LRAFO), and the magnitude of the order parameter, and then compare with results of spin wave theory. An ordered phase also exists when electrons are itinerant. In this case, the growth in the antiferromagnetic structure factor coincides with the transition from band insulator to metal in the absence of interactions.

Compressible ferrimagnetism in the depleted periodic Anderson model

“…An example of the former is Lieb's theorem 25 , which rigorously demonstrates that a 1/4-depleted square lattice possesses ground state ferrimagnetic behavior. Instances of the latter are the 1/5-depleted square lattice which can explain spin liquid behavior in CaV 4 O 9 26,27 , and the 1/3-depleted square lattice which shed light into the properties of layered nickelates such as La 4 Ni 3 O 8 [28][29][30] . In these situations, the depletion converts the initial single band nature to a model with multiple bands.…”

Electron doped layered nickelates: Spanning the phase diagram of the cuprates

“…In this context, the recently synthesized low valence layered nickelates (R 4 Ni 3 O 8 , R438, with R= La or Pr) with an average Ni valence of +1.33, are promising candidates to investigate. [9][10][11][12][13][14][15][16] Particularly, Pr438, a 1/3 self hole doped (relative to d 9 ) line compound, stands among the closest bulk analogs to high-T c cuprates. It shows metallic behavior and a large orbital polarization with holes in the planar d x 2 −y 2 states, as well as a high degree of O-p-Nid hybridization.…”