Large anomalous Nernst effect and topological Nernst effect in the noncollinear antiferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>NdMn</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Ge</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Chunqiang Xu, Wei Tian, Pengpeng Zhang, Xianglin Ke
Abstract
${\mathrm{ThCr}}_{2}{\mathrm{Si}}_{2}$-type ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ was recently proposed to be a magnetic skyrmion candidate exhibiting the topological Hall effect. In this work, we report magnetic, electronic, and thermoelectric measurements for ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ single crystals. We show that, in the canted antiferromagnetic phase and the conical magnetic phase with a large out-of-plane ferromagnetic component, this system exhibits both an anomalous Nernst effect and a topological Nernst effect. We argue that ${\mathrm{NdMn}}_{2}{\mathrm{Ge}}_{2}$ is a unique magnetic material, with its topological characteristics associated with the Berry phases in both real space and momentum space.