Field-induced intermediate ordered phase and anisotropic interlayer interactions in α − RuCl 3

$\\ensuremath{\\alpha}$-RuCl${}_{3}$ exhibits an intermediate-field ordered state at fields below the transition to the disordered phase. The latter state may be related to the Kitaev quantum spin liquid. Several measurements including neutron diffraction show that the intermediate state is magnetically ordered with a periodicity perpendicular to the plane doubled compared to the order at zero field. This can be explained by accounting for spin-anisotropic interplane interactions, showing that a three-dimensional model is necessary to capture the physics of $\\ensuremath{\\alpha}$-RuCl${}_{3}$.