Magnetic properties of the putative higher-order topological insulator EuIn$_2$As$_2$

Abstract

In higher-order topological insulator (HOTI), a gap is preserved both for the bulk and the surface states, and only hinges or corners become gapless. Recently, it has been predicted that the antiferromagnetic compound EuIn_22As_22 can host both the HOTI and axion insulator features. Preliminary experimental confirmation of this finding was obtained using angle-resolved photoemission spectroscopy. The main objective of this work was to characterize the anisotropic magnetic properties of single-crystalline EuIn_22As_22. In addition, complementary studies on the transport properties, heat capacity, and magnetocaloric effect in this compound were performed.