In-gap spin excitations and finite triplet lifetimes in the dilute singlet ground state system SrCu(2-x)Mgx(BO3)2.
High resolution neutron scattering measurements on a single crystal of SrCu(2-x)Mgx(BO3)2 with x approximately 0.05 reveal the presence of new spin excitations within the gap of this quasi-two-dimensional, singlet ground state system. The application of a magnetic field induces Zeeman-split states associated with S=1/2 unpaired spins which are antiferromagnetically correlated with the bulk singlet. Substantial broadening of both the one- and two-triplet excitations in the doped single crystal is observed, as compared with pure SrCu2(BO3)2. Theoretical calculations using a variational algorithm and a single quenched magnetic vacancy on an infinite lattice are shown to qualitatively account for these effects.
Haravifard
S
S
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada.
Dunsiger
S R
SR
El Shawish
S
S
Gaulin
B D
BD
Dabkowska
H A
HA
Telling
M T F
MT
Perring
T G
TG
Bonca
J
J