Abstract
The bicollinear antiferromagnetic order experimentally observed in FeTe is shown to be stabilized by the
coupling ~g12 between monoclinic lattice distortions and the spin-nematic order parameter with B2g
symmetry, within a three-orbital spin-fermion model studied with Monte Carlo techniques. A finite but
small value of ~g12 is required, with a concomitant lattice distortion compatible with experiments, and a
tetragonal-monoclinic transition strongly first order. Remarkably, the bicollinear state found here displays
a planar resistivity with the “reversed” puzzling anisotropy discovered in transport experiments.
Orthorhombic distortions are also incorporated, and phase diagrams interpolating between pnictides
and chalcogenides are presented. We conclude that the spin-lattice coupling we introduce is sufficient to
explain the challenging properties of FeTe.
