An ab initio derivation method for effective low-energy Hamiltonians of material with strong spin-orbit interactions

Ab initio Derivation of Low-Energy Hamiltonians for Systems with Strong Spin-Orbit Interaction and Its Application to Ca5Ir3O12

We present an ab initio derivation method for effective low-energy low-energy electronic structures of material with strong spin-orbit interactions.Based on this formalism and the developed code, we derive an effective low-energy electronic structure of a strong spin-orbit interaction material, which consists of three edge-shared edge-shared iro6 octahedral chains arranged along the c axis, and the three ir atoms in the ab plane compose a triangular lattice.We found that a density-functional band structure near the fermi level is formed by local dxy and dyz orbitals.The nearest neighbor transfer integral involved in the spin-orbit interaction is 0.2 ev, which is comparable to the onsite exchange integral near 0.2 ev, indicating that the spin-orbit-interaction physics would compete with the hund physics.