High-temperature expansion for frustrated magnets: Application to the J1-J2 model on the BCC lattice

TL;DR

This paper develops high-temperature series expansions for the frustrated J1-J2 Heisenberg model on the BCC lattice, analyzing thermodynamic properties and critical temperature dependence on frustration.

Contribution

It provides the first high-order series expansions for specific heat, susceptibility, and structure factor for this frustrated lattice model, including critical temperature estimation.

Findings

High-temperature series up to 11th order for specific heat and susceptibility.

Series up to 9th order for structure factor.

Critical temperature dependence on frustration parameter J2.

Abstract

We present the high-temperature expansion up to 11th order for the specific heat $C$ and the uniform susceptibility $\chi_0$ and up to 9th order for the structure factor $S_{\bf Q}$ of the frustrated spin-half $J_1$-$J_2$ Heisenberg model on the BCC lattice. We consider ferromagnetic as well as antiferromagnetic nearest-neighbor exchange $J_1$ and frustrating antiferromagnetic next-nearest-neighbor exchange $J_2$. We discuss the influence of frustration on the temperature dependence of these quantities. Furthermore, we use the HTE series to determine the critical temperature $T_c$ as a function of the frustration parameter $J_2$.