title: Excitations from a Bose-Einstein condensate of magnons in coupled spin ladders.
abstract: The weakly coupled quasi-one-dimensional spin ladder compound (CH3)2CHNH3CuCl3 is studied by neutron scattering in magnetic fields exceeding the critical field of Bose-Einstein condensation of magnons. Commensurate long-range order and the associated Goldstone mode are detected and found to be similar to those in reference to spin-dimer materials. However, for the upper two massive magnon branches, the observed behavior is totally different, culminating in a drastic collapse of excitation bandwidth beyond the transition point.
authors.affiliation: Neutron Scattering Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.
authors.forename: V O
authors.initials: VO
authors.lastname: Garlea
authors.forename: A
authors.initials: A
authors.lastname: Zheludev
authors.forename: T
authors.initials: T
authors.lastname: Masuda
authors.forename: H
authors.initials: H
authors.lastname: Manaka
authors.forename: L-P
authors.initials: LP
authors.lastname: Regnault
authors.forename: E
authors.initials: E
authors.lastname: Ressouche
authors.forename: B
authors.initials: B
authors.lastname: Grenier
authors.forename: J-H
authors.initials: JH
authors.lastname: Chung
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.forename: K
authors.initials: K
authors.lastname: Habicht
authors.forename: K
authors.initials: K
authors.lastname: Kiefer
authors.forename: M
authors.initials: M
authors.lastname: Boehm