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MA: Fachverband Magnetismus

MA 40: Frustrated Magnets II

MA 40.9: Vortrag

Donnerstag, 21. März 2024, 17:15–17:30, H 1058

Kitaev-Heisenberg model on the star lattice -- from chiral Majoranas to chiral triplons — •Peru d'Ornellas¹ and Johannes Knolle^1,2,3 — ¹Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom — ²Department of Physics TQM, Technische Universitat Munchen, James-Franck-Straße 1, D-85748 Garching, Germany — ³Munich Center for Quantum Science and Technology (MCQST), 80799 Munich, Germany

The interplay of frustrated interactions and lattice geometry can lead to a variety of exotic quantum phases. Here we unearth a particularly rich phase diagram of the Kitaev-Heisenberg model on the star lattice, a triangle decorated honeycomb lattice breaking sublattice symmetry. In the antiferromagnetic regime, the interplay of Heisenberg coupling and geometric frustration leads to the formation of valence bond solid (VBS) phases -- a singlet VBS and a bond selective triplet VBS stabilized by the Kitaev exchange. We show that the ratio of the Kitaev versus Heisenberg exchange tunes between these VBS phases and chiral quantum spin liquid regimes. Remarkably, the VBS phases host a whole variety of chiral triplon excitations with high Chern numbers in the presence of a weak magnetic field. We discuss our results in light of a recently synthesized star lattice material and other decorated lattice systems.

Keywords: Kitaev; Heisenberg; VBS; triplon; chiral