Abstract:

The Kitaev model on a honeycomb lattice predicts a special quantum spin liquid (QSL) ground state with excitations resembling Majorana Fermions and gauge flux excitations. These emergent features are exciting prospects to both basic physics and applications towards a lossless technology for quantum qubits. In this talk, I will describe our recent range of experiments on the magnetic Mott insulator alpha-RuCl3 which has honeycomb layers held together with weak van-der-Waals interactions. A strong spin-orbit coupling and an octahedral crystal field makes the Kitaev interactions arguably the leading order term in the Hamiltonian. Prominently, despite a long-range ordered ground state, our neutron scattering measurements reveal a continuum of fractionalized excitations resembling predictions from Majorana Fermions, confirming that the material is proximate to a QSL. In a 8T magnetic field the long-range order vanishes and the continuum becomes gapped, giving rise to hopes of a state where a direct evidence of non-Abelian excitations can be measured. I will describe the future endeavors that may help to stabilize the coherent quantum excitations allow a better understanding of the underlying physics.