Dynamical and finite temperature properties of Kitaev magnet beta-Li2IrO3 in magnetic field*

We present theoretical study of the field-induced magnetic phases in the three-dimensional, hyperhoneycomb Kitaev compound beta-Li2IrO3. We show that a relatively weak magnetic field along the crystallographic b-axis drives the system from its incommensurate counter-rotating order to a correlated paramagnet, with a significant uniform ‘zigzag’ component superimposing the magnetization along the field. We compute the magnon excitation spectra, the dynamical spin structure factors and their polarization dependence and argue that our results provide additional distinctive fingerprint that can be checked experimentally. Finally, using extensive Monte Carlo simulations, we study the evolution of the magnetic orders with temperature and provide the finite temperature phase diagram of field-induced magnetic phases.