Anomalous Nernst effect in a ferrimagnetic nodal-line semiconductor Mn$_3$Si$_2$Te$_6$

TL;DR

This study reports a significant anomalous Nernst effect in the ferrimagnetic nodal-line semiconductor Mn$_3$Si$_2$Te$_6$, linked to its topological nodal-line features and magnetic properties, with potential implications for topological spintronics.

Contribution

It demonstrates the presence of a sizable anomalous Nernst signal in Mn$_3$Si$_2$Te$_6$ and links it to the material's topological nodal-line structure and magnetism, highlighting a novel interplay.

Findings

Sizable anomalous Nernst signal observed below T_c

Enhanced Nernst-magnetization scaling ratio in low magnetic fields

Correlation between Nernst effect and topological nodal-line topology

Abstract

In the ferrimagnetic nodal-line semiconductor Mn$_3$Si$_2$Te$_6$, colossal magnetoresistance (CMR) arises below $T_\mathrm{c}=78$ K due to the interplay of magnetism and topological nodal-line fermiology. The Berry curvature associated with the topological nodal-line is expected to produce an anomalous Nernst effect. Here, we present sizable anomalous Nernst signal in Mn$_3$Si$_2$Te$_6$ below $T_\mathrm{c}$. In the low-magnetic-field region where CMR is most apparent, the scaling ratio between the Nernst signal and magnetization is significantly enhanced compared to that in conventional magnetic materials. The enhanced Nernst effect and CMR likely share the same mechanisms, which are closely linked to the nodal-line topology.