Plaquette valence bond state in spin-1/2 J1-J2 XY model on square lattice

We studied the ground-state phase diagram of spin-1/2  𝐽1−𝐽2 𝑋⁢𝑌 model on the square lattice with first-neighbor 𝐽1 and second-neighbor 𝐽2 antiferromagnetic interactions using both infinite density matrix renormalization group (iDMRG) and DMRG approaches. We show that a plaquette valence bond phase is realized in an intermediate region 0.50≤𝐽2/𝐽1<0.54 between a Néel magnetic ordered phase at 𝐽2/𝐽1<0.50 and a stripy magnetic ordered phase at 𝐽2/𝐽1≥0.54. The plaquette valence bond phase is characterized by finite dimer orders in both the horizontal and vertical directions. Contrary to the spin-1/2 𝐽1−𝐽2 Heisenberg model, we do not find numerical evidence for a quantum spin liquid phase in the 𝐽1−𝐽2 𝑋⁢𝑌 model.