Triplet and singlet excitations in the valence bond crystal phase of the kagome lattice Heisenberg model

Rajiv R.P. Singh, David A. Huse

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

A proposed ground state for the kagome lattice Heisenberg model consists of a valence bond crystal (VBC) with a 36-site unit cell. We calculate the low-lying triplet and singlet excitations in the VBC phase for the infinite-lattice model and for the 36-site cluster. For the infinite lattice, the lowest triplet excitation is found to have a spin gap of approximately 0.08±0.02J and a bandwidth of only about 0.01J. For the 36-site cluster, which consists of a single unit cell with periodic boundary conditions, there are substantial finite-size effects: the spin gap there is estimated to be approximately 0.2J, which is close to the exact diagonalization result of 0.164J. The triplet excitations attract one another and form many bound states in the spin-singlet channel. We find a large number of such bound states for the 36-site cluster, many of which appear to lie below the spin gap, which is again in agreement with the results from exact diagonalization.

Original languageEnglish (US)
Article number144415
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume77
Issue number14
DOIs
StatePublished - Apr 17 2008

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Triplet and singlet excitations in the valence bond crystal phase of the kagome lattice Heisenberg model'. Together they form a unique fingerprint.

  • Cite this