Generalized plaquette state in the anisotropic Shastry-Sutherland model

• Main Authors: Zhang, Zhifeng, Sengupta, Pinaki
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2015
• Subjects: Physics and Applied Physics
• Online Access: https://hdl.handle.net/10356/81122; http://hdl.handle.net/10220/39133
• Institution: Nanyang Technological University

We use a generalized Schwinger boson approach to investigate the nature of the intermediate phase (separating the antiferromagnetic and dimer phases) in the Shastry-Sutherland model with exchange anisotropy. Our results confirm the plaquette nature of the intermediate phase and demonstrate that exchange anisotropy (both Ising-like and XY-like) weakens the plaquette order and ultimately suppresses it altogether for sufficiently strong anisotropy. Interestingly, we find that the low-energy excitation spectrum of the plaquette state changes dramatically near the boundary with the dimer phase—the location of the minimum in the (gapped) lowest excitation mode changes from k=(0,0) to four degenerate points.