Two-Dimensional Iron Silicide (FeSix) Alloys with Above-Room-Temperature Ferromagnetism

Yijie Niu; Kai Zhang; Xuefeng Cui; Xiaojun Wu; Jinlong Yang

doi:10.1021/acs.nanolett.3c00113

Two-Dimensional Iron Silicide (FeSi_x) Alloys with Above-Room-Temperature Ferromagnetism

Nano Lett. 2023 Mar 22;23(6):2332-2338. doi: 10.1021/acs.nanolett.3c00113. Epub 2023 Mar 10.

Authors

Yijie Niu¹, Kai Zhang^{1

2}, Xuefeng Cui^{2

3}, Xiaojun Wu^{1

2

3}, Jinlong Yang^{1

2

3}

Affiliations

¹ CAS Key Laboratory for Materials for Energy Conversion, School of Chemistry and Materials Science, CAS Center for Excellence in Nanoscience and Synergetic Innovation of Quantum Information & Quantum Technology, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
³ Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China.

PMID: 36897107
DOI: 10.1021/acs.nanolett.3c00113

Abstract

Two-dimensional (2D) materials with intrinsic room-temperature ferromagnetism have gathered tremendous interest as promising candidates for next-generation spintronics. Here, on the basis of first-principles calculations, we report a family of stable 2D iron silicide (FeSi_x) alloys via dimensional reduction of their bulk counterparts. Our results demonstrate that 2D Fe₄Si₂-hex, Fe₄Si₂-orth, Fe₃Si₂, and FeSi₂ nanosheets are lattice-dynamically and thermally stable, confirmed by the calculated phonon spectra and Born-Oppenheimer dynamic simulation up to 1000 K. 2D FeSi_x nanosheets are ferromagnetic metals with estimated Curie temperatures ranging from 547 to 971 K due to strong direct exchange interaction between Fe sites. In addition, the electronic properties of 2D FeSi_x alloys can be maintained on silicon substrates, providing an ideal platform for spintronics applications in the nanoscale.

Keywords: ferromagnets; first-principles; iron silicides; two-dimensional material.