title: Energy separation of single-particle and continuum states in an S = 1/2 weakly coupled chains antiferromagnet
abstract: Inelastic neutron scattering is used to study transverse-polarized magnetic excitations in the quasi-one-dimensional S = 1/2 antiferromagnet BaCu2Si2O7, where the saturation value for the Neel order parameter is m(0) = 0.12&mgr;(B) per spin. At low energies the spectrum is totally dominated by resolution-limited spin-wave-like excitations. An excitation continuum sets in above a well-defined threshold frequency. Experimental results are discussed in the context of current theories for weakly interacting quantum half-integer-spin chains.
authors.affiliation: Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.initials: A
authors.lastname: Zheludev
authors.initials: M
authors.lastname: Kenzelmann
authors.initials: S
authors.lastname: Raymond
authors.initials: E
authors.lastname: Ressouche
authors.initials: T
authors.lastname: Masuda
authors.initials: K
authors.lastname: Kakurai
authors.initials: S
authors.lastname: Maslov
authors.initials: I
authors.lastname: Tsukada
authors.initials: K
authors.lastname: Uchinokura
authors.initials: A
authors.lastname: Wildes