Spin orders and excitation in frustrated Heisenberg model with four-spin exchange interaction

Abstract

In this work, we study the phase diagram of a frustrated Heisenberg model with the additional next nearest neighbor four-spin interaction accounting for the spin–lattice coupling in order to understand the magnetism of iron tellurium. The experimentally identified bicollinear ground state that is always degenerate with the plaquette state in any Heisenberg-biquadratic models [Glasbrenner et al., Nat. Phys. 11, 953 (2015)] and the first-order phase transition are well reproduced, strongly confirming the essential role of the four-spin interaction related to the spin–lattice coupling [Bishop, Moreo, and Dagotto, Phys. Rev. Lett. 117, 117201 (2016)] in explaining the magnetic properties of iron tellurium. Moreover, based on the linear spin-wave theory, specific magnetic excitation in strained iron tellurium is predicted, appealing for experimental verification.