MLZ ist eine Kooperation aus:
> Technische Universität München> Helmholtz-Zentrum Hereon > Forschungszentrum JülichMLZ ist Mitglied in:
MLZ in den sozialen Medien:
MLZ
Lichtenbergstr.1
85748 Garching
Kitaev spin liquid remains an intriguing and elusive state of matter. In this talk, I will review iridate compounds as material prototypes of the Kitaev spin model, and focus on the possibility of using hydrostatic pressure for tuning these materials toward the anticipated spin-liquid state.
The A2IrO3 iridates are proximate to a dimerization transition that shortens the Ir-Ir distances and suppresses local magnetism. Both α- and β-Li2IrO3 undergo such a transition around 3.7 GPa, but the β-phase additionally shows a first-order transition around 1.4 GPa, where long-range magnetic order is suppressed without the loss of local magnetism. Using a combination of thermodynamic and local probes as well as band structure calculations, we suggest that above 1.4 GPa β-Li2IrO3 enters the classical spin liquid phase with part of the spins frozen below 15 K. This is accompanied by an increase in the off-diagonal anisotropy Γ and a decrease in the Kitaev exchange K, in contrast to the original expectations of enhancing Kitaev magnetism under pressure.
I will further present recent results on the hexahalide Ir-based antifluorite compounds K2IrCl6 and K2IrBr6, where large single crystals can be grown from the solution. These compound entail the frustrated face-centered cubic arrangement of the Ir4+ ions and may be proximate to the ideal jeff=½ state, although we detect symmetry lowering in K2IrBr6 as well as a soft rotary mode in K2IrCl6, suggesting the proclivity of these compounds to structural distortions. Magnetic transitions are accompanied by structural anomalies, suggesting a strong coupling between magnetism and lattice. Moreover, large single crystals render neutron-scattering experiments more feasible than in any other iridium compounds studied to date.
Datum | 03.12.2018 |
Uhrzeit | 14:30 - 15:30 Uhr |
Ort | Garching / Physik Department |
Raum | HS 3 |
Sprecher | Dr. Alexander Tsirlin, University of Augsburg |
Veranstalter | TUM / MLZ |
Kontakt | |
Ansprechpartner | Dr. Markos Skoulatos und Dr. Alexandros Koutsioumpas |
URL |
MLZ ist eine Kooperation aus:
> Technische Universität München> Helmholtz-Zentrum Hereon > Forschungszentrum JülichMLZ ist Mitglied in:
MLZ in den sozialen Medien: