Doped bilayer antiferromagnets: Hole dynamics on both sides of a magnetic ordering transition

Article

关键词: T-J MODEL;    HIGH-TEMPERATURE SUPERCONDUCTIVITY;    SPIN-WAVES;    HEISENBERG-ANTIFERROMAGNET;    QUANTUM ANTIFERROMAGNETS;    2-LAYER ANTIFERROMAGNET;    CUMULANT APPROACH;    STATE;    BI2SR2CACU2O8+DELTA;    FLUCTUATIONS;   

DOI  :  10.1103/PhysRevB.60.15201

来源: SCIE

【 摘 要 】

The two-layer square lattice quantum antiferromagnet with spins 1/2 shows a magnetic order-disorder transition at a critical ratio of the interplane to intraplane couplings. We investigate the dynamics of a single hole in a bilayer antiferromagnet described by a t-J Hamiltonian To-model the spin background we propose a ground-state wave function for the undoped system that covers both magnetic phases and includes transverse as well as longitudinal spin fluctuations. The photoemission spectrum is calculated using the spin-polaron picture for the whole range of the ratio of the magnetic couplings. This allows for the study of the hole dynamics on both sides of the magnetic order-disorder transition. For:small interplane coupling we find a quasiparticle with properties known from the single-layer antiferromagnet, e.g., the dispersion minimum is at (+/-pi/2, +/-pi/2). For large interplane coupling the hole dispersion is similar to that of a free fermion (with reduced bandwidth). The crossover between these two scenarios occurs inside the antiferromagnetic phase, which indicates that the hole dynamics is governed by the local environment of the hole. [S0163-1829(99)04245-9].

【 授权许可】

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