title: Excitations in a four-leg antiferromagnetic Heisenberg spin tube.
abstract: Inelastic neutron scattering is used to investigate magnetic excitations in the quasi-one-dimensional quantum spin-liquid system Cu(2)Cl(4).D(8)C(4)SO(2). Contrary to previously conjectured models that relied on bond-alternating nearest-neighbor interactions in the spin chains, the dominant interactions are actually next-nearest-neighbor in-chain antiferromagnetic couplings. The appropriate Heisenberg Hamiltonian is equivalent to that of a S=1/2 4-leg spin-tube with almost perfect one dimensionality and no bond alternation. A partial geometric frustration of rung interactions induces a small incommensurability of short-range spin correlations.
authors.affiliation: Neutron Scattering Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. garleao@ornl.gov
authors.forename: V O
authors.initials: VO
authors.lastname: Garlea
authors.forename: A
authors.initials: A
authors.lastname: Zheludev
authors.forename: L-P
authors.initials: LP
authors.lastname: Regnault
authors.forename: J-H
authors.initials: JH
authors.lastname: Chung
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.forename: M
authors.initials: M
authors.lastname: Boehm
authors.forename: K
authors.initials: K
authors.lastname: Habicht
authors.forename: M
authors.initials: M
authors.lastname: Meissner