## The Kitaev material α-RuCl_3: Transient quantum magnetic state, unusual magnetic excitations, chiral phonons, and more

**Abstract:** One way to characterize quantum spin-liquids is through the fractionalization of spin excitations. A prime example of this is found in the exactly solvable Kitaev model of spin-1/2 moments with anisotropic exchange interactions on a tri-coordinated lattice. To find examples of this kind of physics in nature turns out to be challenging. The currently best-known examples of materials in which Kitaev-like physics plays a central role are the layered spin-orbit entangled J=1/2 systems Na2IrO3, α-Li2IrO3, and α-RuCl3.