Mechanically strong and room-temperature magnetocaloric monolayer VSi2N4 semiconductor

Abstract

In the realm of emerging two-dimensional MoSi2N4 family, the majority of research endeavors gravitate toward their versatile physical properties, while their magnetocaloric effect (MCE) for the potential refrigeration application remains uncharted. Here, we comprehensively explore the magnetic, electronic, mechanical, and magnetocaloric properties of monolayer VA2Z4 (A = Si, Ge; Z = N, P, As) family by multiscale simulations, revealing that monolayer VSi2N4 semiconductor is mechanically strong and exhibits room-temperature MCE. The nonlinear elastic response of VSi2N4 unveils strong mechanical properties, featuring a substantial in-plane Young's modulus (E2D∼ 350 N/m) and a high strength of 40.8 N/m, comparable to that of graphene. Monolayer VSi2N4 exhibits a room-temperature MCE with an extensive refrigeration temperature range up to 20 K. Furthermore, applying biaxial strain can significantly improve the maximum magnetic entropy change (−ΔSMmax) and maximum adiabatic temperature change (ΔTadmax) by 80.9% and 197.3%, respectively. Room-temperature MCE with wide working temperature and mechanical robustness make monolayer VSi2N4 an appealing candidate for magnetic refrigeration applications over large temperature range. These findings offer fresh insights for advancing the development of magnetic cooling in small-sized systems.