Quantum phase transitions and the 1/3 magnetization plateau in the spin-1/2 Ferromagnetic–Ferromagnetic–Antiferromagnetic chain

Guang-Hua Liu a,n , Wei Li b , Wen-Long You c , Gang Su d , Guang-Shan Tian e

a Department of Physics, Tianjin Polytechnic University, Tianjin 300387, PR China b Department of Physics, Beihang University, Beijing 100191, PR China c School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006, PR China d Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, College of Physical Sciences, University of Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049, PR China e School of Physics, Peking University, Beijing 100871, PR China

The ground-state properties of the spin-1/2 Ferromagnetic–Ferromagnetic–Antiferromagnetic (F–F–AF) trimerized chain are investigated by the infinite time-evolving block decimation (iTEBD) method. A ground-state phase diagram including three different phases, i.e., a fully polarized phase, a 1/3 plateau phase, and a non-plateau phase, is obtained. All the quantum phase transitions (QPTs) can be described well by the model independent bipartite entanglement. QPTs between the non-plateau phase and the other two phases belong to the second-order category. Doubly degenerate entanglement spectrum and nontrivial string order are observed in the 1/3 plateau phase, which can be used to distinguish it from the other phases. By the scaling behavior of the bipartite entanglement, the central charge of the critical nonplateau phase is determined to be c≃ 1.