Spinon signatures in the critical phase of the (1,1/2) ferrimagnet in a magnetic field

Article

关键词: MATRIX RENORMALIZATION-GROUP;    LOW-TEMPERATURE PROPERTIES;    SPIN-1/2 HEISENBERG CHAIN;    QUANTUM;    THERMODYNAMICS;    STATES;    ANTIFERROMAGNETS;    BEHAVIOR;    SYSTEMS;    MODELS;   

DOI  :  10.1103/PhysRevB.59.13565

来源: SCIE

【 摘 要 】

We propose an effective theory for the critical phase of a quantum ferrimagnetic chain with alternating spins 1 and 1/2 in an external magnetic field. With the help of the matrix product variational approach, the system is mapped to a spin-1/2 XXZ chain in an (effective) magnetic field; as a by-product, we obtain an excellent description of the optical magnon branch in the gapped phase. Recent finite-temperature density matrix renormalization group results for the low-temperature part of the specific heat are well described by the present approach, and the pop-up peaks, developing near the critical field values and in the middle of the critical phase, are identified with the contributions from two different spinon bands of the effective spin-1/2 chain. The effect should be observable as well in other spin-gap systems in an external field, particularly in spin ladders.

【 授权许可】

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