Giant Nernst Angle in Self-Intercalated van der Waals Magnet Cr1.25Te2

The discovery of two-dimensional van der Waals (vdW) magnetic materials has propelled advancements in technological devices. The Nernst effect, which generates a transverse electric voltage in the presence of a longitudinal thermal gradient, shows great promise for thermoelectric applications. In this work, we report the electronic and thermoelectric transport properties of Cr_1.25Te₂, a layered self-intercalated vdW material which exhibits an antiferromagnetic ordering at T_N ∼ 191 K followed by a ferromagnetic-like phase transition at T_C ∼171 K. We observe a prominent topological Hall effect and topological Nernst effect between T_C and T_N, which is ascribable to non-coplanar spin textures inducing a real-space Berry phase due to competing ferromagnetic and antiferromagnetic interactions. Furthermore, we show that Cr_1.25Te₂ exhibits a substantial anomalous Nernst effect, featuring a giant Nernst angle of ∼37% near T_C and a maximum Nernst thermoelectric coefficient of 0.52 μV/K. These results surpass those of conventional ferromagnets and other two-dimensional vdW materials, highlighting Cr_1.25Te₂ as a promising candidate for advanced thermoelectric devices based on the Nernst effect.