Frustrated magnets and quantum paramagnetic phases at finite temperature

Abstract

We develop a general framework, which combines exact diagonalization in small clusters with a density matrix variational principle, to study frustrated magnets at finite temperature. This thermodynamic hierarchical mean-field technique is used to determine the phase diagram and magnetization process of the three-dimensional spin-1/2 $J_1$-$J_2$ antiferromagnet on a stacked square lattice. Its non-magnetic phase exhibits a thermal crossover from a quantum to a classical paramagnet at a temperature $T=T_0$ which can be extracted from thermodynamic measurements. At low temperature an applied magnetic field stabilizes, through order-by-disorder, a variety of phases with non-trivial spin textures and a magnetization plateau at half-saturation which continuously disappears at $T\sim T_0$. Our results are relevant for frustrated vanadium oxides.

TeXLive (Unix), revtex4-1, 5 pages, 4 figures

References in corpus (6)

• Ground-state phases of the spin-1/2 J_1-J_2 Heisenberg antiferromagnet on the square lattice: A high-order coupled cluster treatment
• Quantum $J_1$--$J_2$ antiferromagnet on the stacked square lattice: Influence of the interlayer coupling on the ground-state magnetic ordering
• Pinwheel VBS state and triplet excitations in the two-dimensional deformed kagome lattice
• Hierarchical mean-field approach to the $J_1$-$J_2$ Heisenberg model on a square lattice
• Frustrated spin-1/2 square lattice in the layered perovskite PbVO(3)
• Quantum fluctuations in high field magnetization of 2D square lattice J1-J2 antiferromagnets

Cited by in corpus (1)

• Staircase of crystal phases of hard-core bosons on the Kagome lattice