Ground-state properties for bilayer Kitaev model: dimer expansion study

TL;DR

This paper investigates the ground state of the bilayer Kitaev model using high-order dimer expansion, revealing the stability of the dimer singlet state across a broad parameter range.

Contribution

It introduces a dimer expansion method with symmetry considerations to analyze the bilayer Kitaev model's ground state properties.

Findings

Dimer singlet state is stable over a wide parameter region.

Ground state energy and correlations expanded up to 30th order.

Parity symmetries reduce computational complexity.

Abstract

We study ground state properties in the bilayer Kitaev model by means of the dimer expansion. The existence of parity symmetries in the system reduces the computational cost significantly. This allows us to expand the ground state energy and interlayer spin-spin correlation up to 30th order in the interdimer Kitaev coupling. The numerical calculations clarify that the dimer singlet state is indeed realized in the wide parameter region.