Thermodynamic properties of the XX model in a chain with a period two and three coupling

Abstract

The exact solutions for the energy spectrum of the XX model with a periodic coupling and an external transverse magnetic field $h$ are obtained. The diagonalization procedure is discussed, and analytical and numerical solutions are given. Using the solutions for period-two coupling, the free energy, entropy, and specific heat are calculated as functions of temperature and applied transverse external magnetic field. Their expressions show that below a particular value $v$ and above a value $u$ of the magnetic field $|h|$, the entropy and the specific heat vanish exponentially in the low temperature limit.

20 pages, 9 figures, new references added

References in corpus (2)

• Regularly alternating spin-1/2 anisotropic XY chains: The ground-state and thermodynamic properties
• Level Spectroscopy: Physical Meaning and Application to the Magnetization Plateau Problems