Two-dimensional(2D)ferromagnetic materials have been discovered with tunable magnetism and orbital-driven nodal-line features.Controlling the 2D magnetism in exfoliated nanoflakes via electric/magnetic fields enables a boosted Curie temperature(Tc)or phase transitions.One of the challenges,however,is the realization of high Tc 2D magnets that are tunable,robust and suitable for large scale fabrication.Here,we report molecular-beam epitaxy growth of wafer-scale Fe3+xGeTe2 films with Tc above room temperature.By controlling the Fe composition in Fe3+xGeTe2,a continuously modulated Tc in a broad range of 185-320 K has been achieved.This widely tunable Tc is attributed to the doped interlayer Fe that provides a 40％enhancement around the optimal composition X=2.We further fabricated magnetic tunneling junction device arrays that exhibit clear tunneling signals.Our results show an effective and reliable approach,i.e.element doping,to producing robust and tunable ferromagnetism beyond room temperature in a large-scale 2D Fe3+xGeTe2 fashion.

Shanshan Liu;Zihan Li;Ke Yang;Enze Zhang;Awadhesh Narayan;Xiaoqian Zhang;Jiayi Zhu;Wenqing Liu;Zhiming Liao;Masaki Kudo;Takaaki Toriyama;Yunkun Yang;Qiang Li;Linfeng Ai;Ce Huang;Jiabao Sun;Xiaojiao Guo;Wenzhong Bao;Qingsong Deng;Yanhui Chen;Lifeng Yin;Jian Shen;Xiaodong Han;Syo Matsumura;Jin Zou;Yongbing Xu;Xiaodong Xu;Hua Wu;Faxian Xiu

State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China;Institute for Nanoelectronic Devices and Quantum Computing,Fudan University,Shanghai 200433,China;College of Science,University of Shanghai for Science and Technology,Shanghai 200093 China;Laboratory for Computational Physical Sciences(MOE),Fudan University,Shanghai 200433,China;Solid State and Structural Chemistry Unit,Indian Institute of Science,Bangalore 560012,India;School of Electronic Science and Engineering,Nanjing University,Nanjing 210093,China;Department of Physics,University of Washington,Seattle,WA 98195-1560,USA;Department of Electronic Engineering,Royal Holloway University of London,Egham TW20 OEX,UK;Materials Engineering,The University of Queensland,Brisbane QLD 4072,Australia;Beijing Key Laboratory of Microstructure and Property of Advanced Materials,Institute of Microstructure and Property of Advanced Materials,Beijing University of Technology,Beijing 100124,China;The Ultramicroscopy Research Center,Kyushu University,Fukuoka 819-0395,Japan;State Key Laboratory of ASIC and System,School of Microelectronics,Fudan University,Shanghai 200433,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing 210093,China;Department of Applied Quantum Physics and Nuclear Engineering,Kyushu University,Fukuoka 819-0395,Japan;Centre for Microscopy and Microanalysis,The University of Queensland,Brisbane QLD 4072,Australia;Shanghai Research Center for Quantum Sciences,Shanghai 201315,China

国家科学评论（英文版）

[1]Shanshan Liu;Zihan Li;Ke Yang;Enze Zhang;Awadhesh Narayan;Xiaoqian Zhang;Jiayi Zhu;Wenqing Liu;Zhiming Liao;Masaki Kudo;Takaaki Toriyama;Yunkun Yang;Qiang Li;Linfeng Ai;Ce Huang;Jiabao Sun;Xiaojiao Guo;Wenzhong Bao;Qingsong Deng;Yanhui Chen;Lifeng Yin;Jian Shen;Xiaodong Han;Syo Matsumura;Jin Zou;Yongbing Xu;Xiaodong Xu;Hua Wu;Faxian Xiu-.Tuning 2D magnetism in Fe3+xGeTe2 films by element doping)[J].国家科学评论（英文版）,2022(06):158-165

Fe3+xGeTe2

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