Quantum effects in a weakly frustrated s=1/2 two-dimensional heisenberg antiferromagnet in an applied magnetic field.
We have studied the two-dimensional S=1/2 square-lattice antiferromagnet Cu(pz)_{2}(ClO4)_{2} (where pz denotes pyrazine), using neutron inelastic scattering and series expansion calculations. We show that the presence of antiferromagnetic next-nearest-neighbor interactions enhances quantum fluctuations associated with resonating valence bonds. Intermediate magnetic fields lead to a selective tuning of resonating valence bonds and a spectacular inversion of the zone-boundary dispersion, providing novel insight into 2D antiferromagnetism in the quantum limit.
Tsyrulin
N
N
Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
Pardini
T
T
Singh
R R P
RR
Xiao
F
F
Link
P
P
Schneidewind
A
A
Hiess
A
A
Landee
C P
CP
Turnbull
M M
MM
Kenzelmann
M
M