Ferromagnetic–ferromagnetic–antiferromagnetic–antiferromagnetic correlation and magnetization plateau in spin-1/2 J1–J1–J2–J2 tetrameric chains

Abstract The magnetization process of a spin-1/2 J1–J1–J2–J2 tetrameric Heisenberg chain is investigated by the infinite time-evolving block decimation (iTEBD) method. A magnetization phase diagram including three different phases, i.e., a fully polarized (FP) phase, a 1/2 plateau phase, and a spin-fluid (SF) phase, is obtained. All the quantum phase transitions (QPTs) are determined to belong to the second-order category, and the central charge in the critical SF phase equals 1. In addition, a 1/2 plateau phase also exists in the classical J1–J1–J2–J2 tetrameric Ising chain. The F–F–AF–AF (or AF–AF–F–F) type longitudinal correlation is found to be important and necessary for the appearance of the 1/2 plateau state in both quantum and classical cases.