SKM 2023 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 52: Frustrated Magnets: Strong Spin-Orbit Coupling

TT 52.9: Vortrag

Donnerstag, 30. März 2023, 17:15–17:30, HSZ 201

Triple-Q order in Na₂Co₂TeO₆ from proximity to hidden-SU(2)-symmetric point — •Wilhelm Krüger¹, Wenjie Chen², Xianghong Jin², Yuan Li^2,3, and Lukas Janssen¹ — ¹Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, TU Dresden, 01062 Dresden, Germany — ²International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China — ³Collaborative Innovation Center of Quantum Matter, Beijing 100871, China

In extended Heisenberg-Kitaev-Gamma-type spin models, hidden-SU(2)-symmetric points are isolated points in parameter space that can be mapped to pure Heisenberg models via nontrivial duality transformations. Such points generically feature quantum degeneracy between conventional single-Q and exotic multi-Q states. We argue that recent single-crystal inelastic neutron scattering data place the honeycomb magnet Na₂Co₂TeO₆ in proximity to such a hidden-SU(2)-symmetric point. The low-temperature order is identified as a triple-Q state arising from the Néel antiferromagnet with staggered magnetization in the out-of-plane direction via a 4-sublattice duality transformation. This state naturally explains various distinctive features of the magnetic excitation spectrum, including its surprisingly high symmetry and the dispersive low-energy and flat high-energy bands. Our result demonstrates the importance of bond-dependent exchange interactions in cobaltates, and illustrates the intriguing magnetic behavior resulting from them.