Li, X;
Cooper, SE;
Krishnadas, A;
de la Torre, A;
Perry, RS;
Baumberger, F;
Silevitch, DM;
... Feng, Y; + view all
(2021)
Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr2IrO4.
Physical Review B
, 104
(20)
, Article L201111. 10.1103/PhysRevB.104.L201111.
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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 IrO 6 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 J eff = 1 / 2 pseudospins, the spin excitations are quasielastic and continuous to 10 meV, potentially hosting a gapless quantum spin liquid in Sr2IrO4.
| Type: | Article |
|---|---|
| Title: | Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr2IrO4 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevB.104.L201111 |
| Publisher version: | https://doi.org/10.1103/PhysRevB.104.L201111 |
| Language: | English |
| Additional information: | Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10139435 |
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