title: Ising phases of Heisenberg ladders in a magnetic field.
abstract: We show that Dzyaloshinskii-Moriya (DM) interactions can substantially modify the phase diagram of spin-1/2 Heisenberg ladders in a magnetic field provided they compete with exchange. For nonfrustrated ladders, they induce a local magnetization along the DM vector that turns the gapless intermediate phase into an Ising phase with broken translational symmetry, while for frustrated ladders, they extend the Ising order of the half-integer plateau to the surrounding gapless phases of the purely Heisenberg case. Implications for experimental ladder and dimer systems are discussed.
authors.affiliation: Research Institute for Theoretical Solid State Physics and Optics, H-1525 Budapest, P.O.B. 49, Hungary.
authors.forename: Karlo
authors.initials: K
authors.lastname: Penc
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Fouet
authors.forename: Shin
authors.initials: S
authors.lastname: Miyahara
authors.forename: Oleg
authors.initials: O
authors.lastname: Tchernyshyov
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mila