2134/34332 Satoshi Nishimoto Satoshi Nishimoto Vamshi M. Katukuri Vamshi M. Katukuri Viktor Yushankhai Viktor Yushankhai Hermann Stoll Hermann Stoll Ulrich K. Roessler Ulrich K. Roessler Liviu Hozoi Liviu Hozoi Ioannis Rousochatzakis Ioannis Rousochatzakis Jeroen van den Brink Jeroen van den Brink Strongly frustrated triangular spin lattice emerging from triplet dimer formation in honeycomb Li2IrO3 Loughborough University 2018 untagged Physical Sciences not elsewhere classified 2018-08-06 15:49:07 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Strongly_frustrated_triangular_spin_lattice_emerging_from_triplet_dimer_formation_in_honeycomb_Li2IrO3/9409094 Iridium oxides with a honeycomb lattice have been identified as platforms for the much anticipated Kitaev topological spin liquid: the spin-orbit entangled states of Ir4+in principle generate precisely the required type of anisotropic exchange. However, other magnetic couplings can drive the system away from the spin-liquid phase. With this in mind, here we disentangle the different magnetic interactions in Li2IrO3, a honeycomb iridate with two crystallographically inequivalent sets of adjacent Ir sites. Our ab initio many-body calculations show that, while both Heisenberg and Kitaev nearest-neighbour couplings are present, on one set of Ir-Ir bonds the former dominates, resulting in the formation of spin-triplet dimers. The triplet dimers frame a strongly frustrated triangular lattice and by exact cluster diagonalization we show that they remain protected in a wide region of the phase diagram.