Formation of a gapless quantum spin liquid upon orbital ordering in a chain

The exchange mechanism of the ordering of electrons on e _g orbitals has been estimated by the quantum Monte Carlo method with the nclusion of the hopping integrals through an anion in a one-dimensional system. A magnetic state in the form of a gapless quantum spin liquid has been found. The plateau existence region in the field-dependence of the magnetization, as well as the wave vector of the modulation of the magnetic structure with Q = π/2 in the (magnetic field-exchange alternating) plane, is determined.