Neighboring correlations are considered for a two-dimensional hard-core boson model on square lattice within Bethe approximation for the clusters consisting of two and four nodes. Explicit equations are derived for the determination of critical temperatures of charge and superfluid ordering and their solutions are considered for various ratios of the parameter of between-centers charge correlations to the transfer integral. It is demonstrated that assumption of neighboring correlations for the temperatures of charge ordering results in the appearance of the critical concentration of bosons, which restricts the existence domain of the solutions of charge ordering type. In the case of superfluid ordering with the assumption of neighboring correlations, the critical temperature is reduced up to zero values at half filling. A phase diagram of the hard-core boson model is constructed with the assumption of phase separation within Maxwell construction and it is shown that consideration of neighboring correlations within Bethe approximation quantitatively approximates the form of phase diagram to the results of Monte Carlo quantum method.
Original languageEnglish
Pages (from-to)1546-1552
Number of pages7
JournalPhysics of the Solid State
Volume63
Issue number10
DOIs
Publication statusPublished - 2021

    GRNTI

  • 29.00.00 PHYSICS

    Level of Research Output

  • VAK List

    WoS ResearchAreas Categories

  • Physics, Condensed Matter

    ASJC Scopus subject areas

  • Condensed Matter Physics

ID: 29482797