Ordering and excitation in orbital compass model on a checkerboard lattice

Joji Nasu, Synge Todo, Sumio Ishihara

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We study an orbital compass model on a checkerboard lattice where orbital degree of freedom is represented by the pseudospin operator. Competition arises from an Ising interaction for the z component of pseudospins along the vertical/horizontal bonds and an Ising interaction for the x component along diagonal bonds. Classical and quantum compass models are analyzed by utilizing several analytical methods and numerical simulations. At a fully frustrated point where the two Ising interactions compete with each other, a macroscopic number of orbital configurations are degenerate in a classical ground state. This degeneracy is lifted by thermal and quantum fluctuations, and a staggered long-range order of the z component of the pseudospin is realized. A tricritical point for this order appears due to competition between the bond dependent Ising interactions. Roles of geometrical frustration on excitation dynamics are also examined.

Original languageEnglish
Article number205141
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number20
DOIs
Publication statusPublished - 2012 May 29

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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