Power-Law Behavior of Bond Energy Correlators in a Kitaev-type Model with a Stable Parton Fermi Surface

TL;DR

This paper investigates bond energy correlations in a Kitaev-type quantum spin model with a stable parton Fermi surface, revealing power-law decay and incommensurate oscillations that characterize a gapless spin liquid.

Contribution

It provides an exact analysis of bond energy correlators in a Kitaev model with a stable Fermi surface, identifying their power-law behavior and singular surfaces in momentum space.

Findings

Bond energy correlations decay as 1/|r|^3 with oscillations.

Identification of singular surfaces in momentum space.

Characterization of a gapless spin liquid state.

Abstract

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, Ref.\[arXiv:1010.1035]. Even though any spin correlations are ultra-short ranged, we find that the bond energy correlations have power law behavior with a $1/|{\bm r}|^3$ envelope and oscillations at incommensurate wavevectors. We determine the corresponding singular surfaces in momentum space, which provide a gauge-invariant characterization of this gapless spin liquid.