Probe and manipulation of magnetism of two-dimensional CrI3 crystal

Abstract

For a long time, it has been generally acknowledged that low-dimensional (lower than three-dimensions) long-range orders cannot stay stable at any finite temperature, because temperature-induced fluctuations can destroy any long-range orders in low-dimensional systems supported by isotropic short-range interactions. However, this theorem requires that the interaction must be short-range and isotropic. In fact, many low-dimensional systems do not meet these two requirements. For example, due to the strong anisotropy in two-dimensional CrI3 crystals, there is a band gap in the magnon spectrum. When the excitation energy from temperature is much lower than the band gap, the magneton cannot be excited by temperature on a large scale, and the long-range magnetic order in the two-dimensional system will not be destroyed. Various methods have been used to characterize the magnetic order in atomically thin CrI3 crystals, and a lot of attempts have been made to manipulate the magnetic structure in the system. Focusing on CrI3, in this article we review the recent studies on growth, magnetic structure measurement and manipulation of two-dimensional magnetic materials, and also discuss the prospects for the next phase of research from the perspectives of basic condensed matter physics research and electronic engineering applications.