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Hubbard-like Hamiltonians are widely used to describe on-site Coulomb interactions in magnetic and strongly-correlated solids, but there is much confusion in the literature about the form these Hamiltonians should take for shells of p and d orbitals. This paper derives the most general s, p and d orbital Hubbard-like Hamiltonians consistent with the relevant symmetries, and presents them in ways convenient for practical calculations. We use the full configuration interaction method to study p and d orbital dimers and compare results obtained using the correct Hamiltonian and the collinear and vector Stoner Hamiltonians. The Stoner Hamiltonians can fail to describe properly the nature of the ground state, the time evolution of excited states, and the electronic heat capacity.
B-site ordered A$_2$BBO$_6$ double perovskites have a variety of applications as magnetic materials. Here we show that diamagnetic $d^{10}$ and $d^0$ B cations have a significant effect on the magnetic interactions in these materials. We present a ne
We report the electronic and magnetic behaviour of the frustrated triangular metallic antiferromagnet 2H-AgNiO2 in high magnetic fields (54 T) using thermodynamic and transport measurements. Here localized d electrons are arranged on an antiferromagn
The discovery of unconventional superconductivity in hole doped NdNiO2, similar to CaCuO2, has received enormous attention. However, different from CaCuO2, RNiO2 (R = Nd, La) has itinerant electrons in the rare-earth spacer layer. Previous studies sh
Developing a theoretical framework for conducting electronic fluids qualitatively distinct from those described by Landaus Fermi-liquid theory is of central importance to many outstanding problems in condensed matter physics. One such problem is that
A quantum spin liquid state has long been predicted to arise in spin-1/2 Heisenberg square-lattice antiferromagnets at the boundary region between Neel (nearest-neighbor interaction dominates) and columnar (next-nearest-neighbor dominates) antiferrom