Nearly degenerate ground states of a checkerboard antiferromagnet and their bosonic interpretation  

作　　者：Haiyuan Zou Fan Yang Wei Ku 

机构地区：[1]Key Laboratory of Polar Materials and Devices(MOE),School of Physics and Electronic Science,East China Normal University,Shanghai 200241,China [2]Department of Physics,Beijing Institute of Technology,Beijing 100081,China [3]Tsung-Dao Lee Institute,Shanghai 200240,China [4]Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education),Shanghai 200240,China [5]Shanghai Branch,Hefei National Laboratory,Shanghai 201315,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第1期84-89,共6页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.12274126);supports from the National Natural Science Foundation of China(Grant Nos.12074031,and 12234016);supports from the National Natural Science Foundation of China(Grant Nos.12274287,and 12042507);the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301900)。

摘　　要：The spin-1/2 model system with antiferromagnetic(AF) couplings on a J1-J2checkerboard lattice, known as the planar pyrochlore model, is strongly frustrated and associated with a two-to-one dimensional crossover. Using the Projected Entangled Simplex States tensor network ansatz, we identify a large number of nearly degenerate states in the frustrated region(J_(1)<J_(2)).Specifically, we find the long-sought crossed-dimer valence bond solid(VBS) state to be the ground state at J_(1)≤J_(2), while various 1D AF correlated states take over the rest. We verify the stability of the VBS state against nematic perturbation. The corresponding bosonic picture provides an intuitive understanding of the low-energy physics. Particularly, it predicts weaker VBS states in the easy-plane limit, which we confirm numerically. Our results clarify the most essential ground state properties of this interesting system and demonstrate the usefulness of bosonic picture in dealing with frustrated magnetism.

关 键 词：tensor networks frustrated magnetism dimensional crossover degenerate states 

分 类 号：O469[理学—凝聚态物理]