In search for correlated quantum states in frustrated magnets we explore the order and excitations in Cs2CuCl4, a quasi-2D spin-1/2 Heisenberg antiferromagnet on an anisotropic triangular lattice, using neutron scattering and high magnetic fields. Unlike conventional magnets with sharp spin-wave excitations, we observe instead dominant excitation continua, as characteristic of fractionalization of spin-1 spin waves into pairs of deconfined spin-1/2 spinons [1,2]. The measured dispersion relations show incommensurate modulations due to the 2D frustrated couplings. The excitation velocity and incommensurate ordering wavevector are largely renormalized from classical values, indicating strong quantum fluctuations in the ground state. In high magnetic fields above saturation spins are fully-polarized in the ground state and the excitations are conventional S=1 spin waves, whose dispersion relation measured by neutron scattering gives the Hamiltonian directly .
Begin WebCam and audio for the whole talk: high bandwidth or medium bandwidth.
Or, begin audio only for the whole talk: high bandwidth or low bandwidth. (Or, right-click to download the whole audio file.)
Begin QuickTime of the whole talk (high bandwidth).
To begin viewing slides, click on the first slide below. (Or, view as pdf.)
Author entry (protected)