Layer effect on thermal expansion in blue phosphorene monolayer and few-layer

The thermal expansion properties of blue phosphorene monolayer, two stacking types of bilayers, and trilayer are investigated by first-principles calculations. It is found all the 2D materials possess negative thermal expansion properties at low temperatures. At high temperatures, only the monolayer retains negative thermal expansion, while the other three turn into positive thermal expansion. The increasing layer number weakens the negative thermal expansion for the 2D materials, resulting from the changes of Gruneisen parameter. The temperature dependent elastic properties are also investigated. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study found that all 2D materials exhibit negative thermal expansion properties at low temperatures, with only the monolayer retaining negative thermal expansion as temperature increases. As the number of layers increases, the negative thermal expansion of 2D materials weakens, due to changes in the Gruneisen parameter. Additionally, the temperature-dependent elastic properties were also investigated.