Acesso Rápido: Docentes | Alunos | Funcionários | Visitantes

Seminário do Grupo de Física Estatística

Data do Evento: 
27/09/2017 - 14:00 até 17:00

Seminário do Grupo de Física Estatística – FGE

“Honeycomb-Lattice Heisenberg-Kitaev Model in a Magnetic Field”

Prof. Dr. Eric de Castro e Andrade - Instituto de Física de São Carlos, IFSC

Dia: 27 de setembro, quarta-feira, às 14h.

Local: Sala de Seminários, Sala 201, Ala 1, do Edifício Principal.

Abstract:

Magnets with strong spin-orbit coupling are currently in the focus of intense research, a primary motivation being the search for novel phases beyond the territory of the spin-isotropic Heisenberg model. Materials with 4d and 5d transition-metal ions have been proposed to host strongly anisotropic exchange interactions between magnetic moments. In particular, the insulating iridates A2IrO3 (A =Na, Li) as well as α-RuCl 3 are promising candidates to realize the Kitaev interaction: Here, the Ir4+ ions are arranged in a layered honeycomb-lattice structure, and the combined effect of spin-orbit coupling, Coulomb interaction, and exchange geometry generates effective S-1/2 moments subject to a combination of compass and Heisenberg interactions, giving rise to Heisenberg- Kitaev models. In this work, we map out the low-T phase diagram of the Heisenberg-Kitaev model, and its extensions, in the semiclassical limit for different field directions. We find a surprisingly rich behavior-very different from that of spin-symmetric Heisenberg models-with a variety of canted phases, including multi-Q and magnetic vortex states. The magnetization processes of the ordered phases are complex, with multiple metamagnetic transitions. We characterize all phases in detail and make concrete proposals to search for them in future experiments.

Data de Término: 
27/09/2017 - 14:00

Desenvolvido por IFUSP