Contributed talk

Spin excitations in 2D triangulene crystals
Antonio T. Costa¹, J. C. G. Henriques^1,2, G. Catarina³, J. Fernández-Rossier^1,4

1 International Iberian Nanotechnology Laboratory (INL), 4715-330 Braga, Portugal
2 Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
3 nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
4 Universidad de Alicante, 03690 San Vicente del Raspeig, Spain

We analyze the spin excitations of two-dimensional honeycomb lattices whose unit cells are composed by pairs of triangulenes. We model the π electrons of the 2D crystals using a Hubbard Hamiltonian. The equilibrium configurations are described within the mean-field approximation by a broken-symmetry state (either ferri- or antiferromagnetic). The spin wave spectral densities are obtained from the transverse spin susceptibility calculated within the random phase approximation (RPA). We compare the RPA results with the predictions of Heisenberg models derived from multi-configuration Hubbard-model calculations for the respective unit cells and find a qualitatively good agreement.