Nanomechanical Characterization of an Antiferromagnetic Topological Insulator

The antiferromagnetic topological insulator MnBi₂Te₄ (MBT) exhibits an ideal platform for investigating unique topological and magnetic properties. While the transport characteristics of magnetic phase transitions in the MBT materials have been extensively studied, the understanding of their mechanical properties and magneto-mechanical coupling remains limited. Here, we utilize nanoelectromechanical systems to probe the intrinsic magnetism in MBT thin flakes through magnetostrictive coupling. By analyzing the mechanical resonance signatures, we explore the magnetic phase transitions from antiferromagnetic (AFM) to canted antiferromagnetic (CAFM) to ferromagnetic (FM) phases as a function of magnetic field. Our results reveal the spin-flop transitions in MBT, characterized by frequency shifts in the mechanical resonance. To establish a correlation between the frequency shifts and the spin-canting states, we employ a magnetostrictive model to extract the magnetostrictive coefficients. Our study demonstrates a valuable approach using nanoelectromechanical systems to investigate magnetic phase transitions, magnetization, and magnetoelastic properties in antiferromagnetic topological insulators.