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

Abstract

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 byproduct, we obtain an excellent description of the optical magnon branch in the gapped phase. Recent finite-temperature DMRG 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 as well observable in other spin-gap systems in an external field, particularly in spin ladders.

4 RevTeX pages, 2 ps figures included

References in corpus (6)

• The spin-1/2 Heisenberg chain: thermodynamics, quantum criticality and spin-Peierls exponents
• Zero Temperature Phase Transition in Spin-ladders: Phase Diagram and Dynamical studies of Cu(Hp)Cl
• Thermodynamics of the (1,1/2) Ferrimagnet in Finite Magnetic Fields
• Magnetic Properties of a Quantum Ferrimagnet: NiCu(pba)(D_2O)_3 . 2D_2O
• Thermodynamics of frustrated quantum spin chains
• Thermodynamic Properties of the Spin-1/2 Antiferromagnetic ladder Cu2(C2H12N2)2Cl4 under Magnetic Field

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• Frustration and Multicriticality in the Antiferromagnetic Spin-1 Chain
• Magnetism and thermodynamics of spin-(1/2,1) decorated Heisenberg chain with spin-1 pendants
• Quantum sine-Gordon dynamics in coupled spin chains
• Modified spin-wave description of the nuclear spin relaxation in ferrimagnetic Heisenberg chains
• Phase diagram of the XXZ ferrimagnetic spin-(1/2, 1) chain in the presence of transverse magnetic field
• Quantum fluctuation effects on the ordered Moments in a two dimensional frustrated ferrimagnet
• Impact of Stealthy Hyperuniform Magnetic Impurity Configurations on Bulk Magnetism in a Two-dimensional Heisenberg Model