Energy separation of single-particle and continuum states in an S = 1/2 weakly coupled chains antiferromagnet
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.
Zheludev
A
Physics Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
Kenzelmann
M
Raymond
S
Ressouche
E
Masuda
T
Kakurai
K
Maslov
S
Tsukada
I
Uchinokura
K
Wildes
A