Magnetization plateaux and jumps in frustrated four-leg spin tubes in magnetic fields

H. D. ROSALES; M. ARLEGO; F. A. GÓMEZ ALBARRACÍN

Journal of Physics: Conference Series

IOP

Lugar: Philadelphia; Año: 2014 vol. 568 p. 42023 - 42027

1742-6588

We study the ground state phase diagram of a frustrated spin-1/2 four-leg tube in an external magnetic field. We explore the parameter space of this model in the regime of all-antiferromagnetic exchange couplings by means of three different approaches: density matrix renormalization group (DMRG), a low-energy effective Hamiltonian (LEH) and a Hartree variational approach (HVA). We find that in the limit of weakly interacting plaquettes, singlet and triplet states play an important role in the formation of magnetization plateaux. We study the transition regions numerically and analytically, and find that they are described, at first order in a strong- coupling expansion, by an XXZ spin-1/2 chain in a magnetic field. These results are consistent with the DMRG and HVA calculations