1. Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr2IrO4
- Author
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Xiang, Li, S. E., Cooper, A., Krishnadas, A., de la Torre, R. S., Perry, F., Baumberger, D. M., Silevitch, D., Hsieh, T. F., Rosenbaum, Yejun, Feng, Xiang, Li, S. E., Cooper, A., Krishnadas, A., de la Torre, R. S., Perry, F., Baumberger, D. M., Silevitch, D., Hsieh, T. F., Rosenbaum, and Yejun, Feng
- Abstract
Protected by the interplay of on-site Coulomb interactions and spin-orbit coupling, Sr₂IrO₄ at high pressure is a rare example of a Mott insulator with a paramagnetic ground state. Here, using optical Raman scattering, we measure both the phonon and magnon evolution in Sr2IrO4 under pressure and identify three different magnetically-ordered phases, culminating in a spin-disordered state beyond 18 GPa. A strong first-order structural phase transition drives the magnetic evolution at ∼10 GPa with reduced structural anisotropy in the IrO₆ cages, leading to increasingly isotropic exchange interactions between the Heisenberg spins and a spin-flip transition to c-axis-aligned antiferromagnetic order. In the disordered phase of Heisenberg Jeff = 1/2 pseudospins, the spin excitations are quasielastic and continuous to 10 meV, potentially hosting a gapless quantum spin liquid in Sr₂IrO₄., source:https://journals.aps.org/prb/abstract/10.1103/PhysRevB.104.L201111
- Published
- 2021