Power-law behavior of bond energy correlators in a Kitaev-type model with a stable parton Fermi surface

We study bond energy correlation functions in an exactly solvable quantum spin model of Kitaev type on the kagome lattice with stable Fermi surface of partons proposed recently by Chua et al. [arXiv:1010.1035v1]. Even though any spin correlations are of ultrashort range, we find that the bond energy correlations have power-law behavior with a 1/vertical bar r vertical bar(3) envelope and oscillations at incommensurate wave vectors. We determine the corresponding singular surfaces in momentum space, which provide a gauge-invariant characterization of this gapless spin liquid.