Metastable Kitaev Spin Liquids in Isotropic Quantum Heisenberg Magnets

Abstract

Metastable states with surprising properties abound in Hilbert space. We study unfrustrated isotropic spin-\half Heisenberg models in honeycomb lattice and find emergence of \textit{metastable Kitaev spin liquids having a 2-spin nematic long range order}, via spontaneous symmetry breaking. Decomposition of isotropic Heisenberg Hamiltonian $H^H$ into an exact sum of 3 noncommuting (permuted) Kitaev Hamiltonians, $H^H$ = $H^{K}_{\rm xyz}+H^{K}_{\rm yzx}+H^{K}_{\rm zxy},$ helps us build a degenerate \textit{manifold of flux free metastable Kitaev spin liquid vacua} and vector Fermionic (Goldstone like) collective modes. We introduce a method, \textit{symmetric decomposition of Hamiltonians}, which might help craft \textit{designer metalstable phases}. It is likely that small Kitaev interactions present in Jackeli-Khaliullin-Kitaev materials, with dominant Heisenberg couplings, bring in metastable Kitaev spin liquid features in real experiments. Present work opens possibilities of performing quantum computation and other tasks, using exotic quasiparticles and exotic metastable states, present in nonexotic real systems.