Talk Title: Spin-1/2 Heisenberg J1-J2 antiferrromagnet on square
lattice We have applied the plaquette renormalization scheme to
study the spin-1/2 frustrated Heisenberg J1-J2 model, on a square lattice with
size 8*8. The ground states are obtained by the variational principle, based on
which the nearest-neighbor spin-spin correlation and the plaquette-order
parameter are investigated. Except the well-known Neel-order and
collinear-order in low and high J2/J1 region respectively, we observe a
plaquette-order in the intermediate region. Meanwhile, Neel order coexists
until J2/J1 reaches 0.6, where the first-order phase transition to
collinear-order occurs. The continuous transition point between the Neel order
and the plaquette order is around 0.45, which needs more detailed
investigations. These values actually agree well with other finite-size
numerical calculation. The kernel of these simulations, the plaquette
contraction, is performed on Graphic Processing Units (GPU) for speedup. Click to download: Presentation File
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