Robust Weak Antilocalization Effect Up to ∼120 K in the van der Waals Crystal Fe5- xGeTe2 with Near-Room-Temperature Ferromagnetism

Zhengxian Li; Deping Guo; Kui Huang; Guodong Ma; Xiaolei Liu; Yueshen Wu; Jian Yuan; Zicheng Tao; Binbin Wang; Xia Wang; Zhiqiang Zou; Na Yu; Geliang Yu; Jiamin Xue; Zhongkai Liu; Wei Ji; Jun Li; Yanfeng Guo

doi:10.1021/acs.jpclett.3c00380

Robust Weak Antilocalization Effect Up to ∼120 K in the van der Waals Crystal Fe_{5- x}GeTe₂ with Near-Room-Temperature Ferromagnetism

J Phys Chem Lett. 2023 Jun 15;14(23):5456-5465. doi: 10.1021/acs.jpclett.3c00380. Epub 2023 Jun 8.

Authors

Zhengxian Li¹, Deping Guo², Kui Huang¹, Guodong Ma³, Xiaolei Liu¹, Yueshen Wu¹, Jian Yuan¹, Zicheng Tao¹, Binbin Wang¹, Xia Wang^{1

4}, Zhiqiang Zou^{1

4}, Na Yu^{1

4}, Geliang Yu³, Jiamin Xue¹, Zhongkai Liu^{1

5}, Wei Ji², Jun Li^{1

5}, Yanfeng Guo^{1

5}

Affiliations

¹ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
² Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100190, China.
³ National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China.
⁴ Analytical Instrumentation Center, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁵ ShanghaiTech Laboratory for Topological Physics, Shanghai 201210, China.

PMID: 37288804
DOI: 10.1021/acs.jpclett.3c00380

Abstract

The van der Waals Fe_5-xGeTe₂ is a 3d ferromagnetic metal with a high Curie temperature of 275 K. We report herein the observation of an exceptional weak antilocalization (WAL) effect that can persist up to 120 K in an Fe_5-xGeTe₂ nanoflake, indicating the dual nature with both itinerant and localized magnetism of 3d electrons. The WAL behavior is characterized by the magnetoconductance peak around zero magnetic field and is supported by the calculated localized nondispersive flat band around the Fermi level. The peak to dip crossover starting around 60 K in magnetoconductance is visible, which could be ascribed to temperature-induced changes in Fe magnetic moments and the coupled electronic band structure as revealed by angle-resolved photoemission spectroscopy and first-principles calculations. Our findings would be instructive for understanding the magnetic exchanges in transition metal magnets as well as for the design of next-generation room-temperature spintronic devices.