Anomalous Hall effect induced by Berry curvature in topological nodal-line van der Waals ferromagnet Fe$_4$GeTe$_2$

Satyabrata Bera; Sudipta Chatterjee; Subhadip Pradhan; Suman Kalyan Pradhan; Sk Kalimuddin; Arnab Bera; Ashis K. Nandy; Mintu Mondal

arXiv · 2308.09695

Anomalous Hall effect induced by Berry curvature in topological nodal-line van der Waals ferromagnet Fe$_4$GeTe$_2$

Satyabrata Bera·Sudipta Chatterjee·Subhadip Pradhan·Suman Kalyan Pradhan·Sk Kalimuddin·Arnab Bera·Ashis K. Nandy·Mintu Mondal

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Abstract

The exploration of nontrivial transport phenomena associated with the interplay between magnetic order and spin-orbit coupling (SOC), particularly in van der Waals (vdW) systems has gained a resurgence of interest due to their easy exfoliation, ideal for two-dimensional (2D) spintronics. We report the near room temperature quasi-2D ferromagnet, Fe$_4$GeTe$_2$ from the iron-based vdW family (Fe$_n$GeTe$_2$, $n$=3,4,5), exhibiting a large anomalous Hall conductivity (AHC), $\sigma^A_{xy}$ $\sim$ 490 $\Omega^{-1}\textrm{cm}^{-1}$ at 2 K. The near quadratic behavior of anomalous Hall resistivity ($\rho^{A}_{xy}$) with the longitudinal resistivity ($\rho_{xx}$) suggests that a dominant AHC contribution is coming from an intrinsic Berry curvature (BC) mechanism. Concomitantly, the electronic structure calculations reveal a large BC arising from SOC induced gaped nodal lines around the Fermi level, governing such large AHC property. Moreover, we also report an exceptionally large anomalous Hall angle ($\simeq$ 10.6\%) and Hall factor ($\simeq$ 0.22 V$^{-1}$) values which so far, are the largest in compared to those for other members in this vdW family.

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Satyabrata Bera, Sudipta Chatterjee, Subhadip Pradhan, Suman Kalyan Pradhan, Sk Kalimuddin, Arnab Bera, Ashis K. Nandy, Mintu Mondal. 2023-08-18. Anomalous Hall effect induced by Berry curvature in topological nodal-line van der Waals ferromagnet Fe$_4$GeTe$_2$. https://arxiv.org/abs/2308.09695

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