First-order quantum phase transition in the orthogonal-dimer spin chain

Article

关键词: EXACT GROUND-STATE;    SYSTEM SRCU2(BO3)(2);    RENORMALIZATION-GROUPS;    HEISENBERG-MODEL;    ANTIFERROMAGNET;    EXCITATIONS;    EXPANSIONS;    PLAQUETTE;    GAP;   

DOI  :  10.1103/PhysRevB.62.5558

来源: SCIE

【 摘 要 】

We investigate the low-energy properties of the orthogonal-dimer spin chain characterized by a frustrated dimer-plaquette structure. When the competing antiferromagnetic couplings are varied, the first-order quantum phase transition occurs between the dimer and the plaquette phases, which is accompanied by nontrivial features due to frustration. besides the discontinuity in the lowest excitation gap at the transition point, a sharp level crossing occurs for the spectrum in the plaquette phase. We further reveal that the plateau in the magnetization curve at 1/4 of the full moment dramatically changes its character in the vicinity of the critical point. It is argued that the first-order phase transition in this system captures some essential properties found in the two-dimensional orthogonal-dimer model proposed for SrCu2(BO3)(2).

【 授权许可】

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