Enhanced magnetoelectric effect near a field-driven zero-temperature quantum phase transition of the spin-1/2 Heisenberg-Ising ladder

Abstract

Magnetoelectric effect of the spin-1/2 Heisenberg-Ising ladder in a presence of the external electric and magnetic fields is rigorously examined by taking into account Katsura-Nagaosa-Balatsky mechanism. It is shown that the applied electric field may control a quantum phase transition between the N\'eel (stripy) ordered phase and the disordered paramagnetic phase. The staggered magnetization vanishes according to a power law with the Ising-type critical exponent 1/8, the electric polarization exhibits a weak singularity and the dielectric susceptibility shows a logarithmic divergence at this particular quantum phase transition. The external electric field may alternatively invoke a discontinuous phase transition accompanied with abrupt jumps of the dielectric polarization and susceptibility on assumption that the external magnetic field becomes nonzero.