Hexagonal-Close-Packed Lattice: Phase Transition and Spin Transport

TL;DR

This study investigates phase transitions and spin transport in a frustrated hexagonal-close-packed lattice with XY and Ising models, revealing critical points and the nature of phase transitions through Monte Carlo simulations.

Contribution

It provides new insights into the critical values and order of phase transitions in frustrated lattices with antiferromagnetic interactions, including spin resistivity behavior.

Findings

Critical ratio for phase transition: 0.5 (Ising), 1/3 (XY).

First-order transition occurs for ta > ta_c, second-order for ta < ta_c.

Spin resistivity peaks at magnetic transition, showing discontinuity in first-order region.

Abstract

We study the ground state (GS) and the phase transition in a hexagonal-close-packed lattice with both XY and Ising models by using extensive Monte Carlo simulation. We suppose the in-plane interaction $J_1$ and inter-plane interaction $J_2$, both antiferromagnetic. The system is frustrated with two kinds of GS configuration below and above a critical value of $\eta=J_1/J_2$ ($\eta_c$). For the Ising case, one has $\eta_c=0.5$ which separates in-plane ferromagnetic and antiferromagnetic states, while for the XY case $\eta_c=1/3$ separates the collinear and non collinear spin configurations. The phase transition is shown to be of first (second) order for $\eta> (<) \eta_c$. The spin resistivity is calculated for the Ising case. It shows a rounded maximum at the magnetic transition in the second-order region, and a discontinuity in the first-order region of $\eta$.