Spin liquid versus long range magnetic order in the frustrated body-centered tetragonal lattice

TL;DR

This paper investigates the competition between magnetic order and spin-liquid states in a frustrated body-centered tetragonal lattice using a novel variational approach, revealing conditions favoring quantum disordered phases.

Contribution

It introduces a variational method decoupling interactions in magnetic and spin-liquid channels, identifying stable magnetic and spin-liquid solutions in the BCT lattice.

Findings

Magnetic orders are stabilized by J1, J2, J3 couplings.

Spin-liquid solutions are energetically competitive, especially under frustration.

A modulated spin-liquid state breaks lattice translation symmetry.

Abstract

The quantum Heisenberg model is studied in the geometrically frustrated body-centered tetragonal lattice(BCT lattice) with antiferromagnetic interlayer coupling J1 and intralayer first and second neighbor coupling J2 and J3. We introduce a variational method: each interaction term can be decoupled partially in the purely magnetic Weiss and in the spin-liquid (SL) mean-field channels. We find that the most stable variational solutions correspond to the three different possible long range magnetic orders that are respectively governed by J1, J2, and J3. We characterize three different purely SL non-magnetic solutions that are variationally the second most stable states after the purely magnetic ones. This suggests that quantum fluctuations induced by the frustration between J1-J2-J3 coupling should destroy magnetic orders and stabilize the formation of SL in large areas of parameters. The SL solution governed by J1 breaks the lattice translation symmetry. This Modulated SL is associated to a commensurate ordering wave vector (1,1,1). We discuss the relevance of our results for heavy fermion Uru2Si2 and cuprate superconductors that have a BCT lattice structure. Also, the general variational method introduced here can be applied to any other system where interaction terms can be decoupled in two different mean-field channels.