Phase diagram and deconfined quantum critical point in the spin-1 bilinear-biquadratic Heisenberg model on a honeycomb lattice

Hui-Hai Zhao (赵汇海)

Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China

zhaohuihai@gmail.com

Abstract：

        We have precisely determined the ground state phase diagram of the spin-1 bilinear-biquadratic Heisenberg model on a honeycomb lattice using the tensor renormalization group method. We find that the ferromagnetic, antiferromagnetic, and ferroquadrupolar phases are stable against quantum fluctuations. However, in the phase where the ground state is staggered quadrupolar ordered in the classical limit, we find that quantum fluctuations suppress completely all magnetic orders and lead to a fully gapped plaquette ordered phase, which breaks the lattice symmetry but preserves the spin symmetry. We also discover that the quantum phase transition between the antiferromagnetic phase and plaquette phase is a direct second order transition, which makes this transition a candidate of deconfined quantum critical point.

时间:2011年9月29日 星期四 下午15:00

地点:四川大学物理学院物理馆三楼学术报告厅323室

四川大学物理学院 理论物理研究中心