Two-Dimensional Intrinsic Half-Metals with Large Spin Gaps

Michael Ashton, Dorde Gluhovic, Susan B. Sinnott, Jing Guo, Derek A. Stewart, Richard G. Hennig

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Abstract

Through a systematic search of all layered bulk compounds combined with density functional calculations employing hybrid exchange-correlation functionals, we predict a family of three magnetic two-dimensional (2D) materials with half-metallic band structures. The 2D materials, FeCl2, FeBr2, and FeI2, are all sufficiently stable to be exfoliated from bulk layered compounds. The Fe2+ ions in these materials are in a high-spin octahedral d6 configuration leading to a large magnetic moment of 4 μB. Calculations of the magnetic anisotropy show an easy-plane for the magnetic moment. A classical XY model with nearest neighbor coupling estimates critical temperatures, Tc, for the Berezinskii-Kosterlitz-Thouless transition ranging from 122 K for FeI2 to 210 K for FeBr2. The quantum confinement of these 2D materials results in unusually large spin gaps, ranging from 4.0 eV for FeI2 to 6.4 eV for FeCl2, which should defend against spin current leakage even at small device length scales. Their purely spin-polarized currents and dispersive interlayer interactions should make these materials useful for 2D spin valves and other spintronic applications.

Original languageEnglish (US)
Pages (from-to)5251-5257
Number of pages7
JournalNano letters
Volume17
Issue number9
DOIs
StatePublished - Sep 13 2017

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All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Ashton, M., Gluhovic, D., Sinnott, S. B., Guo, J., Stewart, D. A., & Hennig, R. G. (2017). Two-Dimensional Intrinsic Half-Metals with Large Spin Gaps. Nano letters, 17(9), 5251-5257. https://doi.org/10.1021/acs.nanolett.7b01367