Abstract
We studied the electronic, magnetic, and optical properties of insulator within the density-functional theory using the generalized gradient approximation taking into account strong Coulomb correlations (GGA+) in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. The x-ray absorption spectra and x-ray magnetic circular dichroism (XMCD) at the Ir edges were investigated theoretically from first principles. The calculated results are in good agreement with experimental data. We found that the GGA+ approach with Hubbard well describes the optical spectra and XMCD spectra at the Ir edges. We investigated the electronic structure of under pressure from first principles. The hyperhoneycomb iridate is on the border of the magnetic ordering with relatively weak Coulomb electron-electron correlations. The undergoes a pressure-induced structural and magnetic phase transitions at GPa with symmetry lowering to the monoclinic . The structural phase transition is accompanied by a dimerization of the previously equally long Ir-Ir bonds. We find remarkable nonmagnetic ground states of at , with a concomitant electronic phase transition from a Mott insulator to band insulators. We found that states are still dominant in the low-energy region in high-pressure monoclinic structure.
2 More- Received 15 May 2018
- Revised 23 October 2018
DOI:https://doi.org/10.1103/PhysRevB.98.245113
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