The Finite-Temperature Behavior of a Triangular Heisenberg Antiferromagnet

We investigate the classical antiferromagnetic Heisenberg model on the triangular lattice with up to third-nearest neighbor couplings using nematic bond theory. This approach allows us to compute the free energy and the neutron scattering static structure factor at finite temperatures. We map out the phase diagram with a particular emphasis on finite-temperature phase transitions that break lattice rotational symmetries, spiral spin liquids and the broad specific heat hump that is ubiquitous in the antiferromagnetic 120 degree phase.