Majorana excitations in Kitaev spin liquids
In recent years, the Kitaev honeycomb model has been the focus of much attention, as it is a solvable example of a quantum spin liquid that hosts exotic Majorana excitations. A potential realization of the model through the Jackeli-Khaliullin mechanism was discussed in real materials with strong spin-orbit coupling. Examples include Na2IrO3 and α-RuCl3. In this talk, I will first review some basic facts about the Kitaev honeycomb model and related materials. Then, I will present our recent results on the optical conductivity in the pure Kitaev honeycomb model. The results obtained suggest that the Majorana excitations are responsible for the low-energy absorption continuum observed in α-RuCl3.