Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA.
Quantum Condensed Matter Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2018 Jun 15;120(24):247201. doi: 10.1103/PhysRevLett.120.247201.
We study the excitation spectrum in the dimer phase of the Shastry-Sutherland model by using an unbiased variational method that works in the thermodynamic limit. The method outputs dynamical correlation functions in all possible channels. This output is exploited to identify the order parameters with the highest susceptibility (single or multitriplon condensation in a specific channel) upon approaching a quantum phase transition in the magnetic field versus the J^{'}/J phase diagram. We find four different instabilities: antiferro spin nematic, plaquette spin nematic, stripe magnetic order, and plaquette order, two of which have been reported in previous studies.
我们使用无偏变分方法研究了 Shastry-Sutherland 模型的二聚体相中激发谱，该方法在热力学极限下工作。该方法输出所有可能通道中的动态相关函数。通过在磁场与 J^{'} / J 相图中接近量子相变时，利用此输出来识别具有最高磁化率（特定通道中单或多三重态凝聚）的序参数。我们发现了四种不同的不稳定性：反铁磁自旋向列、 plaquette 自旋向列、条纹磁有序和 plaquette 有序，其中两种在以前的研究中已有报道。
