Switching magnetization of quantum antiferromagnets: Schwinger boson mean-field theory compared to exact diagonalization

TL;DR

This paper compares the Schwinger boson mean-field theory with exact diagonalization to validate the modeling of magnetization switching in quantum antiferromagnets, highlighting the former's effectiveness for spintronic applications.

Contribution

It demonstrates the consistency between Schwinger boson mean-field theory and exact diagonalization in modeling sublattice magnetization switching, supporting the former's use in quantum antiferromagnet studies.

Findings

Results are consistent within 12.5% deviation at short times.

Both approaches effectively capture the switching process.

The study supports the Schwinger boson method as a versatile framework.

Abstract

Antiferromagnets have attracted significant attention because of their considerable potential in engineering high-density and ultrafast memory devices, a crucial and increasingly demanded component of contemporary high-performance information technology. Theoretical and experimental investigations are actively progressing to provide the capability of efficient switching and precise control of the N\'eel vector, which is crucial for the intended practical applications of antiferromagnets. Recently, a time-dependent Schwinger boson mean-field theory has been successfully developed to study the sublattice magnetization switching in anisotropic quantum antiferromagnets [K. Bolsmann $et \, al.$, \textcolor{blue}{\hyperlink{10.1103/PRXQuantum.4.030332}{PRX Quantum $\mathbf{4}$, 030332 (2023)}}]. Here we use a complementary exact diagonalization method to study such sublattice magnetization switching, but in small-cluster quantum antiferromagnets, by means of an external magnetic field. Furthermore, this article aims to support the findings of the Schwinger boson approach. We show that the results of both approaches are consistent at short time scales, with only about 12.5 $\%$ deviations. The consistency of the outcomes obtained through this alternative exact approach demonstrates that the time-dependent Schwinger boson mean-field theory is a versatile framework to capture the essentials of the switching process in quantum antiferromagnets. Thereby, the findings of current article pave the way for further theoretical and computational progress in the study of antiferromagnets for engineering spintronic devices with ultrahigh density and ultrafast speed.