Phase Transitions in a Coupled Electron and Spin Model on the Shastry-Sutherland Lattice

• Authors: P. Farkašovský , H. Čenčariková
• Languages of publication: EN

Abstracts

EN

The thermodynamics of a simple electron-spin model proposed recently for a description of magnetization processes in rare-earth tetraborides is studied numerically by the canonical Monte Carlo method in two-dimensions. The model is based on the coexistence of two subsystems, and namely, the spin subsystem described by the Ising model and the electronic subsystem described by the free-electron model on the Shastry-Sutherland lattice (SSL). Moreover, both subsystems are coupled by the anisotropic spin-dependent interaction of the Ising type. At T=0 the system exhibits the magnetization plateau (MP) at m/m_s=1/2, 1/3, 1/5, 1/7, 1/9 and 1/11 of the saturated spin magnetization m_s. For the largest phases corresponding to m/m_s=0, 1/3 and 1/2 we have examined the nature of the phase transitions from the low-temperature ordered phase (LTOP) to the high-temperature disordered phase (HTDP). It is shown that all phases persist also at finite temperatures (up to the critical temperature T_c) and that the phase transition at the critical point is of the second order for the m/m_s=0 phase and of the first order for the m/m_s=1/3 and 1/2 phases.

Keywords

EN

75.10.-b; 75.40.Mg; 05.70.Fh

Discipline

• 75.40.Mg: Numerical simulation studies
• 05.70.Fh: Phase transitions: general studies(see also 05.30.Rt Quantum phase transitions in quantum statistical mechanics; 64.70.Tg Quantum phase transitions in specific phase transitions; 73.43.Nq Quantum phase transitions in quantum Hall effects; for superconductivity phase diagrams, see 74.25.Dw; for magnetic phase boundaries, see 75.30.Kz; for ferroelectric phase transitions, see 77.80.B-)
• 75.10.-b: General theory and models of magnetic ordering(see also 05.50.+q Lattice theory and statistics)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2014
• Volume: 126
• Issue: 1
• Pages: 44-45

Dates

published

2014-07

Contributors

author

P. Farkašovský

• Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice, Slovakia

author

H. Čenčariková

• Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice, Slovakia

References

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Identifiers

DOI

10.12693/APhysPolA.126.44