Modulation of Local Magnetization in two-dimensional Axial-Next-Nearest-Neighbor Ising model

TL;DR

This paper investigates the two-dimensional axial-next-nearest-neighbor Ising model at finite temperature, revealing phase transitions and modulation behaviors explained by free-fermion theory using DMRG techniques.

Contribution

It provides a detailed analysis of phase transitions and modulation periods in the 2D ANNNI model using density matrix renormalization group methods.

Findings

Second-order phase transition identified between antiphase and modulated phase.

Modulation period in high-temperature phase explained by free-fermion picture.

Domain wall free energy analysis confirms theoretical predictions.

Abstract

The axial next-nearest-neighbor Ising model is studied in two dimensions at finite temperature using the density matrix renormalization group. The model exhibits phase transition of the second-order between the antiphase in low temperature and the modulated phase in high temperature. Observing the domain wall free energy, we confirm that the modulation period in high-temperature side is well explained by the free-fermion picture.